Re: [CentOS] Enabling X on headless server via network
Dotan Cohen wrote: > On Sun, Jul 25, 2010 at 19:35, Stephen Harris wrote: >> Which shows it's working... but painfully slowly. Bandwidth and especially >> latency is killing you. >> > > Other than getting a new ISP, is there anything that I can do about the > latency? I can smoothly run X over the Internet to the servers I look after only because I myself have a 10mbit/10mbit connection and the servers are either on 50mbit or 100mbit connections but that is not true for all X clients. X can require an incredible amount of bandwidth to be smooth. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Desktop Supercomputer
Rajagopal Swaminathan wrote: > Greetings, > > Thanks Les for your reply. (I dont top-post normally, but this was an > emergency) Emergency? Sorry, but your posts are leading me to think that you have lost it. >> Have you looked at Ubuntu's setup? I don't think it deals with GPU's but it >> might be an easier starting point than building from scratch, and if >> anything >> outgrows your resources it can move to Amazon's ec2. > > The point is, why should we not have and use our own resources? > /me blinks. >> http://www.ubuntu.com/cloud/private >> >> But, I think you need to look at storage and compute facilities differently >> in a >> cloud model. Storage needs to be HA and redundant. Computing needs to be >> able >> to fail and be replaced. > > 1. I am not able to understand your above statement clearly. (see my > earlier replies on this thread) > > 2. I believe (and have experienced including and mother and father), > that nothing and/or everything is (ir)replacable. /me stares. > > 4. I am not confused (See point 1) > Does not seem to be a matter of confusion. You start on this list with a sharing model that sounds akin to time-sharing investments of say a private yacht. Then you post a string of stuff that are rather general, controversial, ill-informed but most of all, nothing to do with Centos. Keep this up and you'll be getting the boot. You've been 'warned' already by Karanbir. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Redundant LAN routing possible?
> Idea being that the dumb switches are used solely for local data > transfer between up to X number of App servers and storage nodes. The > managed switch then handles only external communications as well as > any firewalling. Oh you have dumb switches in the mix? Not going to work as Gordon has said. > > Would connect bond0 to both switches still work without STP in this > kind of a setup, or is this when STP comes in? Or is there a better > network topology, given that I don't have the budget for awsome HP > ProCurves ;) Reusing existing router/switch (DLink DFL-800) and dumb > Gb switches. You don't need HP ProCurves...unless you need good jumboframe support. You will need at least D-Link 3100 switches for what you want. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Redundant LAN routing possible?
Emmanuel Noobadmin wrote: > Thanks for the suggestion, I'll read up more about them. The > bond0 and just works sounds simple which is a Good Thing! The problem > was the last time I tried to cross connect multiple switches, > everything just died so there must be something a bit more involved? > :D > > In the mean time since my post, I came across STP (spanning tree > protocol) that seems to be designed to handle this sort of thing, i.e. > figure out the shortest path and prevent network shortcircuit like > what I had experienced with cross connecting multiple switches. You only really need STP when you have switches that are connected together in such a way as to have multiple paths. For the setup you first posted, you could just have two physically separate networks. That does leave the question of what solution to use to get the boxes to use the other switch if the primary one goes down. So if you connect both networks to make say a big 'circular' network, then you need STP. > > But it apparently takes 50 seconds to reconfigure anytime sometime in > the circuit fails. There is supposedly a Rapid STP that only takes 3 > seconds. Several couple-of-years old search results indicate that it > was tested in 2.4 kernel and will be in 2.6 kernel. However, I cannot > seem to find anything newer that confirms if such functionality is > really in the current kernel. Anybody has any idea? > You probably want to inform the switch which ports are link ports and which ports are edge ports (that is, only hosts will use the port) to reduce the amount of work and therefore time needed. > > > On 7/11/10, Jerry Franz wrote: >> On 7/10/2010 2:21 PM, Emmanuel Noobadmin wrote: >>> I've been reading that it's possible to set up a system with multiple >>> NIC to provide redundant internet connectivity such that it will >>> switch to a secondary connection if the primary ISP fails. >>> >>> Is it possible in a similar way to setup redundant LAN routing? I read >>> that it is possible to aggregate/bond multiple NIC to stackable >>> switches that support link aggregation and redundancy. But if only >>> simple switches are available, is something like this possible? >>> >>> e.g. >>> System A >>> eth0 -> lan switch/router 1 >>> eth1 -> lan switch/router 2 >>> >>> System B >>> eth0 -> lan switch 1 >>> eth1 -> lan switch 2 >>> >>> Then somehow specify that, if lan switch 1 fails, the two systems will >>> switch to using switch 2 so that in case of a switch failure, the >>> network continues to remain operational. >> Yes. You can do it. I've done it before. All you need is the right >> choice of bonding mode . You set up bond0 for eth0 and eth1 and it 'just >> works'. To make it more robust, cross-connect the two switches as well. >> >> -- >> Benjamin Franz >> ___ >> CentOS mailing list >> CentOS@centos.org >> http://lists.centos.org/mailman/listinfo/centos >> > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
Les Mikesell wrote: > Chan Chung Hang Christopher wrote: >> Christopher Chan wrote: >>> On Thursday, July 08, 2010 05:09 PM, Kahlil Hodgson wrote: >>>> On 07/08/2010 05:08 PM, Christopher Chan wrote: >>>>>> Hmmm ... which bond mode are you using? >>>>> Why mode 4 of course. >>>> Ouch. Never used that mode. >>> Huh? Like why? It's the recommended mode unless the switch does not >>> suppoprt it or the boards don't. >>> >> Oh sorry, got a bit grouchy there. I don't like overtime and was getting >> tired too. Did not read your mail properly. >> > > I think some bridge or vlan scenarios require promiscuous mode (and the > corresponding disabling of hardware acceleration). Maybe the real issue is > that > something accidentally disabled it and you now only work when tcpdump > re-enables it. I'm not sure how this is supposed to be managed atomically > when > multiple programs may manipulate it and it needs to be propagated across > multiple bonded nics, but maybe something went wrong there. At least some > things log the change so maybe you can get a hint about when it was turned on > and off. > /me wonders if the loading of the bridge and another related module has anything to do with this. I'll prepare a list of targets for rmmod. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
JohnS wrote: > On Thu, 2010-07-08 at 07:51 -0500, Les Mikesell wrote: >> I think some bridge or vlan scenarios require promiscuous mode (and the >> corresponding disabling of hardware acceleration). Maybe the real issue is >> that >> something accidentally disabled it and you now only work when tcpdump >> re-enables it. I'm not sure how this is supposed to be managed atomically >> when >> multiple programs may manipulate it and it needs to be propagated across >> multiple bonded nics, but maybe something went wrong there. At least some >> things log the change so maybe you can get a hint about when it was turned >> on >> and off. > --- > > Check out /proc/net/bonding/bond/YOUR_BOND. Make sure your slave IDs > are the same as in aggregator ID. If not it will cause the problem your > having. Bad NIC hardware also it's failing over for a reason as the log > showed. > Okay, I'll take a look tomorrow when I get in to work. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
Hakan Koseoglu wrote: > HiChristopher, > > On 08/07/10 10:25, Christopher Chan wrote: Why mode 4 of course. >> Huh? Like why? It's the recommended mode unless the switch does not >> suppoprt it or the boards don't. > I never realised this is the recommended mode. Do you have pointers > where it is recommended so that I can read on why? > Maybe 'the recommended' is a bit too much. But here is a read. http://useopensource.blogspot.com/2010/02/linux-nic-teaming-recommendations.html ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
Christopher Chan wrote: > On Thursday, July 08, 2010 05:09 PM, Kahlil Hodgson wrote: >> On 07/08/2010 05:08 PM, Christopher Chan wrote: Hmmm ... which bond mode are you using? >>> Why mode 4 of course. >> Ouch. Never used that mode. > > Huh? Like why? It's the recommended mode unless the switch does not > suppoprt it or the boards don't. > Oh sorry, got a bit grouchy there. I don't like overtime and was getting tired too. Did not read your mail properly. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] DNS or firewall problem
>> Are you running a proxy for http? It would be rather >> surprising that internal machines can access the Internet >> without forwarding turned on otherwise. When you say internal >> machines cannot access your server, are they connecting to it >> via the local interface's ip or the Internet ip? >> Are the services bound to the local interface? > > > I did notice today there is a squid.conf file in my /etc/httpd/conf.d > directory. It appears it is configure for the local domain only. I renamed > it and restarted apache but that didn't work. > > The server has two nics, one for internet and one for the local network, > connected to a switch. eth0 is connected to the uplink port. Please pastebin the output of the following: Run as root: 'cat /etc/sysconfig/iptables' 'netstat -ntlp' ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
Les Mikesell wrote: > Chan Chung Hang Christopher wrote: >> Christopher Chan wrote: >>> And now the thing is working again... >> It's not working again. >> >> Running tcpdump -i vlan seems to trigger something to get the network >> working again but as soon as I stop tcpdump...nada, zip, zilch. >> >> Any ideas? I see no errors in the logs whether of the switch or the box, >> just about everything reports fine. Would the loading of the kernel >> bridge module cause this? > > Running tcpdump would put the interface in promiscuous mode. Does your setup > need this to work? > I don't think so. The thing was working fine since December last year until this morning. Then poof! I just realized I forgot to boot older kernels to check for the same problem... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Networking just stopped working
Christopher Chan wrote: > And now the thing is working again... It's not working again. Running tcpdump -i vlan seems to trigger something to get the network working again but as soon as I stop tcpdump...nada, zip, zilch. Any ideas? I see no errors in the logs whether of the switch or the box, just about everything reports fine. Would the loading of the kernel bridge module cause this? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS MD RAID 1 on Openfiler iSCSI
Emmanuel Noobadmin wrote: > On 6/29/10, Chan Chung Hang Christopher > wrote: >> gluster don't care about underlying filesystem...it don't support acl >> yet for a reason > > Could you elaborate on that? Although at the moment I don't appear to > have a need for ACL on the storage, it is always good to be aware of > any potential pitfalls. No POSIX acl support let alone NFSv4 ACL support. The sole reason why I have not yet gone Linux samba frontends and OpenSolaris ZFS backends glued together with Gluster. It does support POSIX permissions but that is not specific enough nor close enough to the NTFS security. Other than that, I would have given GlusterFS a go a long time ago. > >>> I think I might be overcomplicating things here. >>> >>> Reading up more on gluster, it seems that I could simply put a gluster >>> client on the application server, mount a volume mirrored on from two >>> gluster servers and let gluster handle the failover transparently. >> /me nods > > Thanks for the confirmation :) > > Also just for the benefit of whoever else in the future looking at the > archives > Just found this link which seems to confirm that Gluster can be used > to share active/active failover storage to multiple machines by > running it on the machines themselves and gives the steps/command to > do it on cloud VM. > > http://rackerhacker.com/2010/05/27/glusterfs-on-the-cheap-with-rackspaces-cloud-servers-or-slicehost/ Define cheap. Like these...er...hmm...creative chums here? http://blog.backblaze.com/2009/09/01/petabytes-on-a-budget-how-to-build-cheap-cloud-storage/ Or how about 7850USD for a 4U, 36 bay ( loaded with 12 x 1TB - not going full out :-( ), multipathing dual SAS host controller + sas backplane, 4 port GB Intel NIC + dual GB Intel NIC, 16GB ECC DDR2 RAM, multiple HT3 links, dual 6 core cpu box? Future 45 bay 4U SAS storage box possible too. No, not putting Centos 5 on that. :-( Not trusting raid5/6. raidz2/raidz3 it is going to be. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS MD RAID 1 on Openfiler iSCSI
Emmanuel Noobadmin wrote: > On 6/29/10, Christopher Chan wrote: >> raid1/iscsi if you have a single host accessing the data or gluster if >> you have more than one host accessing the data... > > This is starting to look really complicated with NCP Storage units on > zfs -> iscsi to gluster unit ext3 since gluster doesn't do zfs -> > multiple application host. gluster don't care about underlying filesystem...it don't support acl yet for a reason > > Wouldn't using both ncp/zfs with gluster be redundant since gluster > does cluster storage to begin with? ??? what cluster storage on ncp??? > > I think I might be overcomplicating things here. > > Reading up more on gluster, it seems that I could simply put a gluster > client on the application server, mount a volume mirrored on from two > gluster servers and let gluster handle the failover transparently. /me nods > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] LSI software raid with centos 5.4
CList wrote: >>> I have been trying to install CentOS 5.4 on a Intel SR1530SHS, Intel > S3200SH >>> mainboard.. It has a 3 x 1TB sata hotswap drives with LSI software raid >>> onboard. >> fake-raid alert! >> >>> I had configured the LSI to have Sata0 and Sata1 with raid 1 and the > third >>> drive as a hotspare drive. >> Okay... >> >>> Format the harddisk and installation was a breeze. The server rebooted > into >>> a blank screen and the cursor just keep blinking. >> Drivers for the LSI fake-raid not included in initrd maybe? >>> Please advise. >> Reinstall and use md raid? > > Will I lose the hotswap capability? > That depends on the controller and driver... Just what LSI board is this? A 3ware board or megaraid or what?!?! ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] LSI software raid with centos 5.4
CList wrote: > Hi, > > I have been trying to install CentOS 5.4 on a Intel SR1530SHS, Intel S3200SH > mainboard.. It has a 3 x 1TB sata hotswap drives with LSI software raid > onboard. fake-raid alert! > > I had configured the LSI to have Sata0 and Sata1 with raid 1 and the third > drive as a hotspare drive. Okay... > > Format the harddisk and installation was a breeze. The server rebooted into > a blank screen and the cursor just keep blinking. Drivers for the LSI fake-raid not included in initrd maybe? > > Please advise. Reinstall and use md raid? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Benchmark Disk IO
Les Mikesell wrote: > On 5/5/2010 12:00 PM, Karanbir Singh wrote: >>> Try to run the same IO operations as your production server is running. >>> Bonnie++ could be good application for benchmarking. Also run some >>> parallel rsync, rm, find, etc proccesses. >>> >> I am with John Pierce on this one, role and app will dictate benchmarks >> that reflect reality. >> >> Having said that, I think iozone> bonnie++ > > If the job involves creating/deleting lots of little files like a mail > server with maildir format storage, you might try to dig up a copy of > postmark too. > Les, you have got to be joking. There is not a single fsync/fsyncdata call in postmark. postmark is completely unsuitable to mimicking mail queues or deliveries to maildirs. I, for one, am glad that Netapp has stopped advertising and have pulled their 'fake' benchmarking utility. It might have been relevant on Linux when it did not have barriers and fsync/fsyncdata had zero guarantees unlike the BSDs and UNIX operating systems. For delivery to maildirs, you want to use fsbench from Bruce Guenter, which does the right thing. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [SOLVED] Re: Installing a CentOS based distro with Raid driver - Citrix XenServer
Georghy wrote: > Chan Chung Hang Christopher a écrit : >> xe dd (assuming you have a floppy [is usb supported?] disk with the drivers) >> > A floppy isn't enough because the driver is about 2.7Mb so I use a USB > Stick. It should be the same with a Floppy. >>> It seems that the system doesn't find the disk, I take a screenshot of >>> errors : >>> >>> here is the lines shown during the splash screen of XenServer : >>> http://img340.imageshack.us/i/capture12.png/ >>> <http://img340.imageshack.us/i/capture12.png/> >>> >>> >> ...I suppose you somehow incorporated the drivers when >> installing...maybe just boot a rescue image and go fix up initrd. Put >> appropriate entries in modprobe.conf and recreate initrd. >> >> > I incorporate the driver during the beginning of the installation phase, > using insmod /megasr.ko > what should I try with modprobe.conf and initrd ? > what is the "rescue image" do you mean a live rescue cd ? > Ah, the rescue mode is probably available with your installation initrd's anaconda. You need to pass rescue to it though...hopefully it works unlike the dd... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [SOLVED] Re: Installing a CentOS based distro with Raid driver - Citrix XenServer
Georghy wrote: > Chan Chung Hang Christopher a écrit : >> Georghy wrote: >> >>> Tru Huynh a écrit : >>> >>>> On Tue, May 04, 2010 at 03:03:00PM +0200, Georghy wrote: >>>> >>>> >>>>> (1)Download that driver : >>>>> http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&ProdId=3117&DwnldID=18570&lang=fra >>>>> from the intel support web site >>>>> >>>>> >>>>> >>>> You should have started your installation with "linux dd" and the initrd >>>> would >>>> have been automatically created for you... (if xenserver works as CentOS-5) >>>> >>>> >>> linux dd doesn't work, because linux label isn't in the boot >>> configuration of XenServer (I tried) >>> >> The installation image just needs a dd kernel parameter that will be >> passed on to anaconda (the installer) no matter what the 'label'. >> ___ >> CentOS mailing list >> CentOS@centos.org >> http://lists.centos.org/mailman/listinfo/centos >> >> > the label by default is "xe" should I try something like xe dd > noprobe=ata1 noprobe=ata2 noprobe=ata3 noprobe=ata4 > or just dd > should I change someting with initrd ? xe dd (assuming you have a floppy [is usb supported?] disk with the drivers) > It seems that the system doesn't find the disk, I take a screenshot of > errors : > > here is the lines shown during the splash screen of XenServer : > http://img340.imageshack.us/i/capture12.png/ > <http://img340.imageshack.us/i/capture12.png/> > ...I suppose you somehow incorporated the drivers when installing...maybe just boot a rescue image and go fix up initrd. Put appropriate entries in modprobe.conf and recreate initrd. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [SOLVED] Re: Installing a CentOS based distro with Raid driver - Citrix XenServer
Georghy wrote: > Tru Huynh a écrit : >> On Tue, May 04, 2010 at 03:03:00PM +0200, Georghy wrote: >> >>> (1)Download that driver : >>> http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&ProdId=3117&DwnldID=18570&lang=fra >>> from the intel support web site >>> >>> >> You should have started your installation with "linux dd" and the initrd >> would >> have been automatically created for you... (if xenserver works as CentOS-5) >> > linux dd doesn't work, because linux label isn't in the boot > configuration of XenServer (I tried) The installation image just needs a dd kernel parameter that will be passed on to anaconda (the installer) no matter what the 'label'. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] OT: Caching synchronous writes
Jure Pečar wrote: >>> Ray Van Dolson wrote: > I think what you want is a proper storage array with mirrored write > cache. > > When ext3 came into widespread use, a popular method to "cache" frequent > fsyncs was to run it in a full data journaling mode, with external journal on > a separate disk. > This turned all random writes to a sequential write, limited to a very small > piece of disk and a periodical journal flush to the real file system. > This worked amazingly well for busy mail queues - throughput went up 10x and > more. People were also reporting improvements in NFS scenarios. Don't know > how this is relevant today in times of SSD, but it should be worth to test it. > > separate disk only? Don't forget nvram sticks or bbu ramdrives. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS5 and samba
Brian Sr wrote: > On Fri, 2010-04-16 at 14:29 +0100, lheck...@users.sourceforge.net wrote: >>> Here's a question: are you using your old configuration files? You might >>> want to compare the default from the install with the old ones - there may >>> be deprecated or defunct or invalid options. >> >> Have used the same smb.conf for years on RHEL3 while moving from 3.0.x to >> 3.[2-4].x. >> > > >does testparm reveal any issues with the config? > He said shares on local filesystems were fine but shares on NFS were borked. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] RAID 5 setup?
Benjamin Franz wrote: > Robert Heller wrote: >> I suspect that this is a simular case to what I did: I have a server >> with 4 drives. I have several (small) RAID1 partitions (/boot, /, >> /usr, /var, etc.) with 4 mirrors and one large RAID5 with three >> partitions and a hot spare (a LVM volumn group, containing /home and >> some other partitions). I would guess that the admin with the "8-way >> RAID1 for the OS" probably also has a 6 or 8 disk RAID5 or RAID6 for >> the bulk of the disks > Yup. 8 way RAID1 for the OS, 8 way RAID6 for the data. I was hoping when > I setup the 8-way RAID1 for the OS that I would get really good read > speeds since md is supposed to stripe reads from RAID1, but in practice > the RAID6 completely kills it for read performance (~61 MB/sec from the > RAID1 partition vs ~200 MB/sec from the RAID6 partition). What are you running? I think there was a patch that evened out the reads across all members as it would at times solely read from one and then another... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] RAID 5 setup?
Benjamin Franz wrote: > Ross Walker wrote: >> No, not yet, but I always recommend setting up your data arrays >> manually so your intimately familiar with how they are constructed and >> the mdadm command usage is fresh in your head. >> >> Did you know with Neil's raid10 implementation you can store 3 copies >> of the data so ANY two drives can fail before you start playing >> Russian roulette! >> > > You can do that with RAID1+0, too. You can setup RAID1 with more than 2 > drives. I have one system with an 8-way RAID1 for the OS. > That's some serious redundancy dude! Good for reads too... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] MySQL max clustering package?
JohnS wrote: > On Tue, 2010-03-16 at 23:19 -0500, Neil Aggarwal wrote: >>> Mysql by itself has built in "clustering" though >>> there can be significant limitations in it depending on your >>> requirements. >> I agree. The built in cluster has too many limitations to >> be useful, but MySQL master-master replication gives a very >> good alternative to a true cluster. We use it to deploy >> geographically redundant systems and it has worked very >> well for us. >> >> Neil > > Well what are your plans when it gets the AXE?? > firebirdsql of course. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Exim VS Postfix (no flame wars please)
Rudi Ahlers wrote: > Can anyone, who has used both Postfix & Exim please share some experience > with me? Which of these 2 did you prefer to use, and why? I have not used exim but I know someone who swears by it. It is highly configurable and had stuff like sender based routing before postfix did. > > cPanel uses Exim (and AFAIK, only Exim), VirtualMin seems to use Postfix by > default and often times when a custom server is installed a client doesn't > know which to use so we recommend Exim. But, what are the differences > between these 2, from your experience, if you don't mind telling me? Exim is monolithic while postfix is not. Next up would be a comparison in feature sets (lookup table should be the same - mysql,pgsql,ldap,Berkerly DB) but is probably not worth it unless you want to do make some really intricate ruleset. The last would probably be the difference in behaviour and therefore in tuning. postfix being non-monolithic might mean that it has more room for fine-tuning than exim. > > I have used Qmail on FreeBSD 4.8 last and don't even consider this as a good > mail system anymore, so I'm not even looking at it right now. > qmail on FreeBSD 4.x? Man, FreeBSD 4.x is dog slow. I got a major performance boost just be moving from FreeBSD to Redhat Linux back in 2002/2003 on the same hardware. FreeBSD also only supports directory indexing to 1000 entries, anymore than that it will start walking through the tree. You do not ever want to build a queue on FreeBSD. Anyway, I would not consider using qmail for an mx but I would for an outgoing server after it has been patched for smtp-auth support. The bottom line is, use whatever you are comfortable with or take the time to learn the mta's behaviours and features. It won't matter how much exim is better than postfix or vice-versa if you are not prepared to work with it. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Motherboards for HPC applications
Eduardo Grosclaude wrote: > On Tue, Mar 9, 2010 at 12:49 AM, Christopher Chan > wrote: >> On Tuesday, March 09, 2010 12:34 AM, Eduardo Grosclaude wrote: >>> Hello, >>> Can somebody recommend CentOS-OK, dual socket motherboards for compute >>> elements? A quick look up at Intel pages suggests they are thinking of >>> them as "server boards", but then they recommend them as "for SMB", >>> I'm somewhat puzzled about it. >>> It would be nice to know what MBs you are using, pros and cons. >>> Thank you in advance >>> >> Could you give us a bit more information on the HPC part? Is this >> clustering or computing? > > I'll be buying a single machine first, building a cluster some time > later. As this second move may be delayed for an unpredictable amount > of time, what I am really interested in is understanding the thought > process a seasoned technician (sysadmin? clusadmin?) may follow when > selecting hardware. > > Do you have high i/o needs? > > Well, perhaps this is my real problem... Don't have enough info about > applications. There are several of them but I think I/O is not at > premium, rather CPU computing is. > If you do not have enough information on the applications, I am afraid it is going to be rather hard to make a final decision. Maybe you want to overspec on the first box, find out what those apps really do and then spec accordingly. Things to consider can include network bandwidth, disk bandwidth. 'bus' bandwidth, memory bandwidth and as John Pierce pointed out, what type of processing. Are the apps single threaded or multi threaded? Single threaded apps might call for the cpus with the highest possible frequencies while multi threaded ones not so much so but how many you can pack into whatever space you have. If cpu processing power is the sole criteria, then why limit to dual-socket boards and not go for quad-socket boards? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Mihai T. Lazarescu wrote: > On Fri, Feb 26, 2010 at 10:34:34AM -0400, Susan Day wrote: > >> On Fri, Feb 26, 2010 at 9:51 AM, Simon Billis wrote: >> Why? >>> That is a good question - I "guess" that google's email system thinks >>> you're >>> sending them spam. If you want your mail to be accepted you may need to >>> have >>> implemented SPF and domainkeys. >> Oh, lovely. As if I didn't have enough work to do...Thanks, google. > > SPF & Co. is a reaction to spam proliferation. You'd better > thank the spammers. :-) Yes, I think they would love to get a nuke for a gift. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Brian Mathis wrote: > On Fri, Feb 26, 2010 at 10:13 AM, Dominik Zyla wrote: > >> And please, stop send mails with html encoding. >> >> -- >> Dominik Zyla >> > > No, do not stop sending emails with HTML encoding. > > Welcome to the second decade of the 21st century. We may not have flying > cars or found the monolith on the moon yet, but at least we can have > proportional fonts with word wrap and basic formatting like bold and > italics. If your mail reader can't handle it, get a new one that can. > Do we have to get into this one? Wave to all the mutt users who just love html tags. Oh, also we should follow the rules of the list so I suppose you can tell me where it says use html on this list and get a capable reader if you do not have one. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Kai Schaetzl wrote: > Chan Chung Hang Christopher wrote on Fri, 26 Feb 2010 22:01:28 +0800: > >> Programmers always have a hard time picking up on the >> system admin side of things. > > Still they should be able to find the best avenue for their questions, or > not? > Fair question. But we don't have to imply certain things. Some people are just touchy not lazy. Hard to deal with the first and bring out the cane for the second when proven. Of course, the clue-by-four should be brought at all times so that we can determine which it is. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Kai Schaetzl wrote: > Susan Day wrote on Fri, 26 Feb 2010 09:25:38 -0400: > >> Sorry, but this has NOT been my experience. I just tried that list >> __last_week__ and __no__ responses, no activity, either. > > Maybe that's because of the nature of your questions. I get the impression > that you are mostly asking very basic questions that a sysadmin *should* > know or at least know how to google them up. I get the impression that you > are not trying hard enough to understand your software. You cannot just > throw any problem you encounter at the next list you find. For your last > two questions (about the python script and this one which also seems to be > related to a script you wrote or use) I get the impression that in both > cases you simply may have bugs in the code or use it incorrectly. These > are then not questions for a mailing list about the MTA nor for this list, > but problems with your code and it might be more helpful to ask on a > mailing list/newsgroup for coders of that language. > Give her a break. Programmers always have a hard time picking up on the system admin side of things. I have had my fights with programmers. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Chan Chung Hang Christopher wrote: >>> postfix has a very active mailing list -- the originator and primary >>> developer, Wietse Venema,responds to posts quite often, as well as >>> many other postfix experts. >>> >>> http://www.postfix.org/lists.html >> >> Sorry, but this has NOT been my experience. I just tried that list >> __last_week__ and __no__ responses, no activity, either. Same with cr.yp.to's >> list. No. If they worked I'd be there. Here's my question again: >> > > Sorry, I do not see your post on the qmail list. Certainly not last week > nor in January either. Nor any post on the postfix list for that matter according to the postfix list archive. Too much traffic for you to stay subscribed I bet. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
>> postfix has a very active mailing list -- the originator and primary >> developer, Wietse Venema,responds to posts quite often, as well as >> many other postfix experts. >> >> http://www.postfix.org/lists.html > > > Sorry, but this has NOT been my experience. I just tried that list > __last_week__ and __no__ responses, no activity, either. Same with cr.yp.to's > list. No. If they worked I'd be there. Here's my question again: > Sorry, I do not see your post on the qmail list. Certainly not last week nor in January either. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
B.J. McClure wrote: > On Fri, 2010-02-26 at 08:57 -0400, Susan Day wrote: > > > >> With respect to Kai's suggestion I find a qmail list, I'm sorry to say >> there don't appear to be ANY discussion lists for ANY email servers >> that are active. I'm desperate to get this working. >> TIA, >> Suzie > > How about > > qmail-h...@list.cr.yp.to That would be the wrong list. qm...@list.cr.yp.to would the correct one. Send email to qmail-subscr...@list.cr.yp.to to subscribe. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Email Problem
Susan Day wrote: > On Fri, Feb 26, 2010 at 8:29 AM, Eero Volotinen wrote: > >> 2010/2/26 Susan Day : >>> Hi; >>> The following message appears to have been sent, but in fact never does >>> reach their destination: >>> >>> [root qmail-send]# tail current >>> >>> @40004b87b3d3392cbddc new msg 97881462 >>> >>> @40004b87b3d3392cc5ac info msg 97881462: bytes 531 from >>> qp 23629 uid 508 >>> >>> @40004b87b3d33b7f700c starting delivery 4: msg 97881462 to remote >>> suzieprogram...@gmail.com >>> >>> @40004b87b3d33b7f7bc4 status: local 0/10 remote 1/255 >>> >>> @40004b87b3d4338aec64 delivery 4: success: >>> >> 209.85.216.35_accepted_message./Remote_host_said:_250_2.0.0_OK_1267184586_6si3416200pxi.53/ >> >> remote end accepted message. >> >>> messages in queue but not yet preprocessed: 0 >>> >>> Why? >> >> Remote smtp server is not working correctly or spamfilter on it kills >> message? >> > > No. How do you know? Remote end accepted responsibility. If it does not get delivered, it is their problem. > >> Note that it can take a bit time until gmail delivers it to mailbox. >> > > Gmail's very quick and it's been an hour now. Usually takes a second. Check spam box. Contact gmail postmaster. Nothing to do with the qmail installation. > Another very strange thing about this is that the contact page refreshes to > itself when I try to email (through the form elt). If I pull the email send > stuff out of the script where the form goes, it doesn't refresh to itself; > rather, it prints what is written in the script to print. > > With respect to Kai's suggestion I find a qmail list, I'm sorry to say there > don't appear to be ANY discussion lists for ANY email servers that are > active. I'm desperate to get this working. You are mistaken. The qmail list and the postfix list are very much active. Only sendmail does not have a discussion list. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] tcpserver on port 25
>> Susan, is qmail-send running? tcpserver is used to run qmail-smtpd to >> accept emails but qmail-send does the actual queue processing and delivery. >> > 27755 ?S 0:00 multilog t s10 n20 /var/log/qmail/qmail-send Susan, why do you say the email server is broken? 'tail -f /var/log/qmail/qmail-send/current' That should indicate activity of qmail in processing and delivering email. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] tcpserver on port 25
Eero Volotinen wrote: > 2010/2/24 Susan Day : >> Hi; >> [r...@13gems beno]# netstat -ltnup >> Active Internet connections (only servers) >> Proto Recv-Q Send-Q Local Address Foreign Address >> State PID/Program name >> tcp0 0 0.0.0.0:33060.0.0.0:* >> LISTEN 24560/mysqld >> tcp0 0 0.0.0.0:110 0.0.0.0:* >> LISTEN 27762/tcpserver >> tcp0 0 0.0.0.0:25 0.0.0.0:* >> LISTEN 27758/tcpserver >> tcp0 0 :::80 :::* >> LISTEN 1598/httpd >> tcp0 0 :::22 :::* >> LISTEN 11453/sshd >> No wonder my email server is broken! How do I move tcpserver off of port 25? > > If you are using qmail, then tcpserver is part of it. > > Usually tcpserver is running under supervise, so you must stop supervised > qmail. Er...i think NOT. Susan, is qmail-send running? tcpserver is used to run qmail-smtpd to accept emails but qmail-send does the actual queue processing and delivery. Do you also use publicfile for serving webpages? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Server HD failed and I think I am hosed
m.r...@5-cent.us wrote: Also, what would have caused this all of the sudden? This box has been running fine for months. >>> Well, do you think that computer hardware lives forever? >>> >> They don't? /me stares at 486dx with a working floppy drive and working >> floppies from the eighties and early nineties. > > And I deal with hardware with drives, and memory, and the occasional m/b > failing at less than five years old. Depends on the manufacturer, the q/c > they had at the time it was manufactured, and the day of the week, as the > old line from car buyers goes. > > mark "make mine on a Wed, please" Haha. This is getting OT but stuff today (for the past decade) do tend to die around the end of warranty if not earlier. No greedy^Wsane company makes anything that lasts anymore. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Server HD failed and I think I am hosed
>> Also, what would have caused this all of the sudden? This box has been >> running fine for months. > > Well, do you think that computer hardware lives forever? > They don't? /me stares at 486dx with a working floppy drive and working floppies from the eighties and early nineties. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 5.4 x86_64 authenticating against AD (Server 2008r2)
Craig White wrote: > On Wed, 2010-02-10 at 09:50 -0500, Ross Walker wrote: >> On Feb 10, 2010, at 8:11 AM, Chan Chung Hang Christopher >> > > wrote: >> >>>> If you have hundreds or thousands of users and hundreds of groups, >>>> well good luck. It is extremely hard to automate assigning these >>>> uids/ >>>> gids and making sure they don't collide with each other or other unix >>>> systems and doing it by hand is a torture reserved for the ninth >>>> circle of hell. >>>> >>>> If only nss_ldap had a SID->UID/GID mapping like samba has. >>>> >>> How about winbind with a ldap backend? winbind creates the uids/gids >>> and >>> the rest just run nss_ldap? >>> >>> I currently use an ldap directory to store the rids but I don't >>> remember >>> if they have been translated to uids/gids or whether the winbind >>> modules >>> do that... >> I don't know either, but if they do, that would work. >> >> Can samba update uid/gidNumbers of existing LDAP directory CNs? >> >> I still like the RID mapping, but if samba can write back uidNumbers >> based on RID map generated uids that would solve the problem. > > In essence, samba knows nothing about writing anything to LDAP but > normally people would install smbldap-tools (not part of samba) to > provide a toolset to write to LDAP. Impossible. winbind certainly knows all about writing to LDAP otherwise it won't be a backend database for rid maps and especially for maintaining the same rids across boxes (okay, this got solved at a higher level and thus an ldap backend is not needed for maintaining identical rids across boxes) and I cannot imagine how that would be accomplished without knowing anything about writing to ldap. > > If smbldap-tools doesn't do what you want, modify it. > ??? What's that? ??? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 5.4 x86_64 authenticating against AD (Server 2008r2)
> If you have hundreds or thousands of users and hundreds of groups, > well good luck. It is extremely hard to automate assigning these uids/ > gids and making sure they don't collide with each other or other unix > systems and doing it by hand is a torture reserved for the ninth > circle of hell. > > If only nss_ldap had a SID->UID/GID mapping like samba has. > How about winbind with a ldap backend? winbind creates the uids/gids and the rest just run nss_ldap? I currently use an ldap directory to store the rids but I don't remember if they have been translated to uids/gids or whether the winbind modules do that... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 5.4 x86_64 authenticating against AD (Server 2008r2)
> Wbinfo -u & wbinfo -g do indeed work for me however getent passwd or getent > group returns no AD users or groups. I have winbind entries in nsswitch for > both the passwd & group entries. Josepeh, I will try a newer RPM from a > different repository and see if that resolves my issues. Did my smb.conf look > ok? > It did...which is why I asked whether wbinfo -u/g worked... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Virtualization software to install Windows as guest on CentOS 5 as host ?
Sergej Kandyla wrote: > Christopher Chan wrote: >> On Thursday, February 04, 2010 03:48 PM, Hadi Motamedi wrote: >> >>> Dear All >>> I need to install Windows as guest on my CentOS 5 as host . Can you >>> please give me the link to download the requierd rpm package for this >>> purpose ? >>> Thank you >>> >> yum install kvm >> >> Then search for virtio drivers. Redhat provides virtio block drivers for >> Windows Vista, 7, 2008. >> > What benefits may provide me the virtio drivers ? They make use of the paravirtualized virtio framework which is orders of magnitude faster than fully virtualized i/o. > Also what suggestions do you have about running win2k3, win2k8 server > as a guests on CentOS5 kvm host ? Well, somebody said use AMD cpus because they are more stable but I have never managed to get that validated. > I'm interesting about disk organization for guest OS at first. If you need performance, you need paravirtualized i/o. With a kvm solution, that means going through virtio. I think Xen has its own solution to this and other than this, I know nothing about vmware and virtualbox on this score. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Centos/Linux Disk Caching, might be OT in some ways
>> Ah, well #1 on his list then is to figure out what he is running! > > LOL, I know it sounds quite noobish, coming across like I've no idea > what DBMS it is running on. The system currently runs on MySQL but > part of my update requirement was to decouple the DBMS so that we can > make an eventual switch to postgresql. > > Hence the solution cannot be dependent on some specific MySQL functionality. mysql's isam tables have a reputation for surviving just about anything and great builtin replication support... postgresql less so (I suspect due to fake fsync/fsyncdata in the days before barriers) but maybe things have improved a lot nowadays. Why are you switching? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] The directory that I am trying to clean up is huge
Anas Alnaffar wrote:
> I tried to run this command
>
> find -name "*.access*" -mtime +2 -exec rm {} \;
>
Should have been: find ./ -name \*.access\* -mtime +2 -exec rm -f {} \;
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Re: [CentOS] 8-15 TB storage: any recommendations?
> On the machine where I had the problem I had to run memtest86 more than a day > to > finally catch it. Then after replacing the RAM and fsck'ing the volume, I > still > had mysterious problems about once a month until I realized that the disks > are > accessed alternately and the fsck pass didn't catch everything. I forget the > commands to compare and fix the mirroring, but they worked - and I think the > centos 5.4 update does that periodically as a cron job now. The other worry > is > that when one drive dies, you might have unreadable spots in normally unused > areas of the mirror since this will keep a rebuild from working - but the > cron > job should detect those too if you notice the results. > I am going to take a good look at the cron jobs on the moodle box then. Need to check whether the ubuntu box does the same. Man, if only I had a Centos cd when the previous gateway died... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
Per Qvindesland wrote: > Hi > > Appologies I have not been following the thread here so am just > wondering if you have a MSA, EVA, XP left hand san or if this is just > storage that sits on the server with samba share? also what link is > between fc or ethernet. If you are asking me, then there is no external direct attach storage. HQ (Bradbury School is an ESF school) provided the thing and it has two disks in mirror mode for a db and four disks in raid5 mode for system and the vle (customized moodle) with a 512 MB BBU module for the P410i controller. They added a 4-port Intel Gigabit adapter too but that is of no consequence with storage right now. > > Regards > Per Qvindesland > > At Tisdag, 12-01-2010 on 11:57 "Chan Chung Hang Christopher" wrote: > > Karanbir Singh wrote: >> On 12/01/10 00:02, Christopher Chan wrote: >>>> problems mostly centered around management and performance issues. > the >>>> world is littered with stores of cciss fail >>> Really? Man, I have been given this spanking new HP DL370 G6 and > running >>> Centos 5.4 on it... >> I've got a couple of DL380's at one setup and another 12 DL360's at >> another place. We have had enough problems with interfaces that all > the >> machines are now running off remote-storage. Our storage incident > rate >> has gone from 1/day average to under 2/month since then. >> >> all of these machines are G4 and G5's running CentOS-5/x86_64 >> > > Eeek! That thing will be hosting the school's vle. Looks like I better > > memorize the after hours password for HP support. > > What problems did you have? Do they occur mostly when the boxes are > under high I/O load? > > This is really new to me as I had no problems with a DL360 G3 box that > > ran Windows 2000 and Exchange 2000 with regards to disk problems in my > > previous job. > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos > > > > > > > > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
Benjamin Donnachie wrote: > 2010/1/12 Chan Chung Hang Christopher : >> Eeek! That thing will be hosting the school's vle. Looks like I better >> memorize the after hours password for HP support. > > I have had lots[1] of problems lately with DIMMs becoming defective in > six month old G5 HPs. Could just be bad luck or maybe just put > together by someone wearing a shell suit. Boy, a Tyan or Supermicro solution is looking better by the minute for the new server I plan to get the school for its library server and other uses. If only Supermicro had a local distributor...I have not had a good look at their solutions yet because of that but their 45 disk case has got my attention. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
>> Which is why I specifically said 'performance wise' as respects 3ware. I >> don't remember anything bad about 3ware stability wise or monitoring wise. > > Is that supposed to be a joke? 3ware has certainly had their fair share of > stability problems (drive time-outs, bbu-problems, inconsistent > behaviour, ...) and monitoring wise they suck (imho). Do you like tw_cli? > Enjoying the fact that "show diag" gives you a cyclic text buffer without > references? etc. Oh, I did not hear of those and my last experience with 3ware was up to the 95xx series. I did hear of horror stories of Mylex but I myself never got to see one of those where the raid configuration would completely disappear. Most of my experience with 3ware is with the 75xx and 85xx cards which are only good for raid1+0 unless you can afford the major performance hit with raid5. > > ...that said, it's not much worse than the competetion, storage simply > sucks ;-( So you are saying people dole out huge amounts of money for rubbish? That the software raid people were and have always been right? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
Karanbir Singh wrote: > On 12/01/10 00:02, Christopher Chan wrote: >>> problems mostly centered around management and performance issues. the >>> world is littered with stores of cciss fail >> Really? Man, I have been given this spanking new HP DL370 G6 and running >> Centos 5.4 on it... > > I've got a couple of DL380's at one setup and another 12 DL360's at > another place. We have had enough problems with interfaces that all the > machines are now running off remote-storage. Our storage incident rate > has gone from 1/day average to under 2/month since then. > > all of these machines are G4 and G5's running CentOS-5/x86_64 > Eeek! That thing will be hosting the school's vle. Looks like I better memorize the after hours password for HP support. What problems did you have? Do they occur mostly when the boxes are under high I/O load? This is really new to me as I had no problems with a DL360 G3 box that ran Windows 2000 and Exchange 2000 with regards to disk problems in my previous job. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
> " Maximum 3.5" hot-swap drives density 36x (24 front + 12 rear) HDD bays" > > http://www.supermicro.com/products/chassis/4U/847/SC847A-R1400.cfm > > Did anybody else think "WTF?" when you saw that picture? > > I have seen crazy stuff, but that one is pretty high-up on the list > > Doesn't that make cooling problematic? And what do you think of the arrangement of the 48 disks in a thumper? Anyway, you can have cooling problems even with 2U cases and just six disks if you have faulty fans so I do not really see a problem with the Supermicro case. You just need working fans. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] 8-15 TB storage: any recommendations?
John Doe wrote: > From: Boris Epstein >> This is not directly related to CentOS but still: we are trying to set up >> some storage servers to run under Linux - most likely CentOS. The storage >> volume would be in the range specified: 8-15 TB. Any recommendations as far >> as hardware? > > Depends on your budget. > Here, we use HP DL180 servers (12 x 1TB disks in 2U)... > You can also check Sun Fire X servers; up to 48 x 1TB in 4U... > Somebody said something about Sun servers being pricey and that quality was going downhill...something about cheap controllers...any comments on this? BTW, the Sun X4540 can only be bought with all disks loaded. So it is not up to 48 but must be 48 in 4U. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Find reason for heavy load
Noob Centos Admin wrote: > Hi, > >> Yes, these figures indicate that you are fairly close to being cpu bound. >> >> What kind of filtering are you doing? If you have any connection >> tracking/state related rules set, you will need to be using a fair >> amount of cpu. > > Initially, when the load start going up, I had thought the APF > filtering rules were the problem since the Indian fellow is still > hammering away at the server even now. However, I've since taken the > risk of turning off APF and rely on static iptables rules, which adds > up to less than one screenful on SSH. I do not know about now but I had to unload the modules in question. Just clearing the rules was not enough to ensure that the netfilter connection tracking modules were not using any cpu at all. > > I also thought it might had to do with exim/spamassassin but making a > few changes to reduce the number of emails that goes to spamd doesn't > seem to be helping much. > > In fact as you can see from the stats, load has gone up even further > since. I've been averaging 10+ for the whole working day. At the > moment it's between 6 to 10 when it should be at 0.3 from past months > of logs. > > This is despite the fact most of my clients should be out celebrating > New Year's Eve. From weeks of logs, the Indian spammer is also a very > punctual fellow who should have knock off work about 17 minutes ago. > So there shouldn't be any heavy 'known' activities on the server at > this point. /me shrugs. When I was the mta admin at Outblaze Ltd. (messaging business now owned by IBM and called Lotus Live) spammers always ensured I got called. All they do is just press the big red button (aka start the script/system) and then go and play while I would have to deal with whatever was started. I remember only one occasion when the spams were launched but neutralized very soon because they were pushing a website and I found a sample real early and so the anti spam system could just dump the spams and knock out accounts being used to send the crap. > > So I'm quite stumped as to what's chewing up the CPU cycles. I am also > starting to worry if the server's been compromised and is now doing > something I don't want it to be. > > I'm probably going to shutdown the mail/httpd services after midnight > when the impact is the least and see how the server reacts for a > couple of minutes with everything else cut off. First, try rmmod'ing the netfilter modules after you have cleared away the state related rules to make sure that you are only using static rules in netfilter...unless you have done that already.. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Find reason for heavy load
Christoph Maser wrote: > Am Donnerstag, den 31.12.2009, 12:34 +0100 schrieb Chan Chung Hang > Christopher: >>>> Look at the first two columns. What column have higher numbers? If r, >>>> you're CPU-bound. If b, you're I/O bound. >>> procs ---memory-- ---swap-- -io --system-- >>> -cpu-- >>> r b swpd free buff cache si sobibo in cs us sy id >>> wa st >>> 8 1 3092 131460 100692 83366800402110 4 1 92 >>> 2 0 >>> 9 1 3092 130708 100700 83501600 578 206 577 1420 32 50 3 >>> 15 0 >>> 7 1 3092 128324 100716 83614800 546 2866 594 1465 31 44 7 >>> 18 0 >>> 4 1 3092 126860 100724 83726800 540 256 596 1505 28 43 6 >>> 23 0 >>> 7 2 3092 125600 100740 83856400 620 234 661 1442 30 41 2 >>> 26 0 >>> 5 1 3092 124028 100756 83975200 570 2692 635 1430 24 45 6 >>> 25 0 >>> 6 0 3092 122040 100784 84096400 584 1464 682 1434 27 44 2 >>> 28 0 >>> 6 1 3092 120588 100792 84223200 602 278 624 1562 32 46 2 >>> 20 0 >>> 2 3 3092 120556 100840 84306400 440 2908 603 1299 22 35 6 >>> 37 0 >>> 3 1 3092 119832 100876 84408800 430 1104 605 1348 23 36 1 >>> 40 0 >>> >>> According to this, am I correct to conclude that I'm CPU bound and the >>> system is busy doing some unknown processing? >> Yes, these figures indicate that you are fairly close to being cpu bound. > > > Really? 20-30% user and ~40% sys/wait look more like I/O to mee. > user accounts for processing done by processes while sys accounts for processing done by the kernel (like netfilter) and idle tells you what is left. idle numbers are below 10 and near 0, that would be what I'd call nearly cpu bound. If he has high idle scores and high wa scores, then he'd be completely i/o bound. The last line there, he got a idle score of 1 while wa was 40 which indicates that even though if there is some i/o waiting, it is not starving the cpus. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Find reason for heavy load
>> Look at the first two columns. What column have higher numbers? If r, >> you're CPU-bound. If b, you're I/O bound. > > procs ---memory-- ---swap-- -io --system-- > -cpu-- > r b swpd free buff cache si sobibo in cs us sy id wa > st > 8 1 3092 131460 100692 83366800402110 4 1 92 2 > 0 > 9 1 3092 130708 100700 83501600 578 206 577 1420 32 50 3 15 > 0 > 7 1 3092 128324 100716 83614800 546 2866 594 1465 31 44 7 18 > 0 > 4 1 3092 126860 100724 83726800 540 256 596 1505 28 43 6 23 > 0 > 7 2 3092 125600 100740 83856400 620 234 661 1442 30 41 2 26 > 0 > 5 1 3092 124028 100756 83975200 570 2692 635 1430 24 45 6 25 > 0 > 6 0 3092 122040 100784 84096400 584 1464 682 1434 27 44 2 28 > 0 > 6 1 3092 120588 100792 84223200 602 278 624 1562 32 46 2 20 > 0 > 2 3 3092 120556 100840 84306400 440 2908 603 1299 22 35 6 37 > 0 > 3 1 3092 119832 100876 84408800 430 1104 605 1348 23 36 1 40 > 0 > > According to this, am I correct to conclude that I'm CPU bound and the > system is busy doing some unknown processing? Yes, these figures indicate that you are fairly close to being cpu bound. What kind of filtering are you doing? If you have any connection tracking/state related rules set, you will need to be using a fair amount of cpu. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Optimizing CentOS for gigabit firewall
Peter Serwe wrote: > I'll second damn near everything nate said, and hopefully add a tidbit or > two. > > If you're new to BSD, you may want to consider the pfsense project in the > aforementioned active-active configuration. > > It gives you a nice, intuitive gui to manage your failover firewalls, if you > insist on putting a firewall in front of your web servers. > > Better to secure the box, leave only the ports you need open on the public > interfaces, and don't firewall them. > > Also, I'd strongly consider running your firewalls with no disk at all. A > Live CD, CF card or USB Flash to boot off of, remote syslog and > one less subsystem (disks) to buy/fail makes for some mighty cheap 1U > servers. A single dual-core with core speeds above 3.0Ghz > and 4GB of RAM is to pass Gb @ line rate - ethernet overhead. Truth be > told, it's already being done on much less /me going to try to get a diskless OpenBSD setup again. > than that. You can also load balance your traffic, albiet somewhat > primitively with it. If you really want massive throughput, consider toying > around with extremely expensive 10G gear, size RAM appropriately, and see > how PF performs under multi-processor, high-core speed. > but if you're handling over a Gb of traffic and you can't split the > application into multiple farms, that's the best move. > That part about high-core speed for OpenBSD pf is definitely on. The multi-processor part...not too sure. Maybe with NUMA systems like what you get on AMD Opteron platforms. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Optimizing CentOS for gigabit firewall
sadas sadas wrote: > The syntax is not a problem. The problem is in the performance. I suppose > that if I configure OpenBSD to process the in/out packets only to layer 2 the > performance will be much more than linux with iptables. > You know SQUAT about filtering on Linux. You want a bridging solution? Then forget about Linux. Even FreeBSD will perform better at bridging firewalling than Linux and OpenBSD is the best performer available. That ipset solution came way after OpenBSD and pf had such a feature and which was already mature and stable too. I should know, I tested ipset while it was still new some years ago. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Optimizing CentOS for gigabit firewall
Les Mikesell wrote: > Timo Schoeler wrote: >>> What about NetBSD? I heard that NetBSD has the best network stack out >>> there. Maybe NetBSD with pf is the best choice? >> NetBSD is a very nice OS, I personally like it most (out of all BSDs out >> there); however, as can be read on >> >> http://www.netbsd.org/docs/network/pf.html >> >> there's the 'usual lag': OpenBSD implements feature X in 4.6, wait some >> time to see it implemented elsewhere. >> >> One of the biggest strengths of OpenBSD is that it's really a completely >> rounded piece of work. Keep it that way. pf will perform best on >> OpenBSD, with all the nice features it has. > > Has anyone used Firewall Builder to create a complex set of iptables > rules? Or compared performance where it built the same thing for > linux/iptables and bsd/pf? > Are you joking? That piece of crap just puts everything into one single chain. I never EVER use Firewall Builder after I saw the results the first time. For a BRIDGING firewall, there is absolutely NO WAY that Linux/netfilter can keep up with OpenBSD/pf. I doubt that Linux/netfilter can even reach half the performance of OpenBSD/pf. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] LVM, usb drives, Active Directory
Steve Thompson wrote: > On Wed, 16 Dec 2009, Chan Chung Hang Christopher wrote: > >> Steve Thompson wrote: >>> On Tue, 15 Dec 2009, Scott Ehrlich wrote: >>> >>>> I have a client with a handful of USB drives connected to a CentOS >>>> box. I am charged with binding the USB drives together into a single >>>> LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap >>>> storage in a single mount point). >>> I tried doing this for fun once upon a time, using 6 1TB drives. I can >>> save you a lot of grief by suggesting that you don't think about this any >>> further. Boy is it slow. And extremely unreliable. And slow. Don't even do >>> it for backups. Did I say it was slow? >> Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or >> slowaris slow? > > Slower than all of those. Top write speed I could ever achieve with a > USB-2 interface and SATA drives was 20 MB/sec with a trailing wind, and > usually half of that, with a single stream. I even tried USB-1 for more > laughs; 1 MB/sec on a truly good day. With multiple writers, performance > dropped so far as to be unusable (below 1 MB/sec). And we're talking mkfs > times in _days_. The host was a CentOS 5.2 box, 32-bit. Kudos to Steve for proving that USB2's 480mbits/sec is really just a sham. Now I wonder if you can daisy chain IEEE1394 devices...or try out eSATA...:-P ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] LVM, usb drives, Active Directory
Scott Ehrlich wrote: > I have a client with a handful of USB drives connected to a CentOS > box. I am charged with binding the USB drives together into a single > LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap > storage in a single mount point). How about eSATA? Surely an eSATA enclosure for 10 drives won't be more expensive than ten individual usb enclosures?! > > The next fun piece is how to incorporate that storage space into an > existing Active Directory structure to apply AD acls for limited > access. AD does not have acls. NTFS does. The closet things to NTFS acls in UNIX is nfs4 acls. That you can get with ZFS. I suggest that you give OpenSolaris a shot instead. Or you can be one of the testers for ntfs-3g's acl implementation... > > I'd rather not use Samba, as that is its own infrastructure and > maintains its own credentials database. Have you ever used winbind? It maps AD credentials to POSIX credentials. > > What are my best options? Stuff not provided by Centos/RHEL at the moment. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] LVM, usb drives, Active Directory
Steve Thompson wrote: > On Tue, 15 Dec 2009, Scott Ehrlich wrote: > >> I have a client with a handful of USB drives connected to a CentOS >> box. I am charged with binding the USB drives together into a single >> LVM for a cheap storage data pool (10 x 1 TB usb drives = 10 TB cheap >> storage in a single mount point). > > I tried doing this for fun once upon a time, using 6 1TB drives. I can > save you a lot of grief by suggesting that you don't think about this any > further. Boy is it slow. And extremely unreliable. And slow. Don't even do > it for backups. Did I say it was slow? > Please qualify 'slow'. Was it dog slow, turtle-slow, snail-slow or slowaris slow? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Using (was: Announcing) Gluster Storage Platform
Alan McKay wrote: > On Tue, Dec 15, 2009 at 7:48 PM, Christopher Chan > wrote: >> A cluster filesystem > > OK, but you've just given me a circular definition. > >> When you do not need/want a cluster file system > > and again ... > Okay, a cluster/distributed file system that does not have its own on disk format. It makes use of whatever existing filesystem there is for actual storage and allows you to replicate files/load balance requests to files to 'storage servers' of any supported platform. At the same time, user level processes on 'clients' access the system as if it was an actual file system. This enables one to have Linux clients that run say samba to export the files to Windows clients but the actual files are kept on OpenSolaris servers on zfs. Should the Linux clients all go down, the Windows clients could still access the files on the OpenSolaris servers via samba. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
>> Write barriers were introduced to give data guarantees with hard drives >> that have their write cache enabled. Unfortunately, not everything has >> been given barrier support. LVM and JFS do not have write barrier support. >> >> > > https://www.redhat.com/archives/dm-devel/2009-December/msg00079.html > > "Barriers are now supported by all the types of dm devices." > > Wunderbar! Now if the IBM team will add barrier support to JFS... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] XFS and LVM2 (possibly in the scenario of snapshots)
Mathieu Baudier wrote: >> LVM like md raid and drbd is a layered block device and >> If you turn the wire caches off on the HDs then there is no problem, >> but HDs aren't designed to perform to spec with the write cache >> disabled they expect important data is written with FUA access (forced >> unit access), so performance will be terrible. >> > > I hope that I'm not going too much off topic here, but I'm getting > worried not to be sure to understand, especially when it has to do > with data safety: > > Considering a stack of: > - ext3 > - on top of LVM2 > - on top of software RAID1 > - on top of regular SATA disks (no hardware RAID) > is it "safe" to have the HD cache enabled? > > (Note: ext3, not XFS, hence the possible off-topic...) > Nothing is safe once device-mapper is involved. > In other words, is this discussion about barriers, etc. only relevant to XFS? No, it applies to all filesystems. Prior to barriers, fsync/fsyncdata lies. See the man page for fsync. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] XFS and LVM2 (possibly in the scenario of snapshots)
Timo Schoeler wrote: > [off list] > > > Thanks for your eMail, Ross. So, reading all the stuff here I'm really > concerned about moving all our data to such a system. The reason we're > moving is mainly, but not only the longisch fsck UFS (FreeBSD) needs > after a crash. XFS seemed to me to fit perfectly as I never had issues > with fsck here. However, this discussion seems to change my mindset. So, > what would be an alternative (if possible not using hardware RAID > controllers, as already mentioned)? ext3 is not, here we have long fsck > runs, too. Even ext4 seems not too good in this area... > I thought 3ware would have been good. Their cards have been praised for quite some time...have things changed? What about Adaptec? >>> Well, for me the recommended LSI is okay as it's my favorite vendor, >>> too. I used to abandon Adaptec quite a while ago and my optinion was >>> confirmed when the OpenBSD vs. Adaptec discussion came up. However, the >>> question on the hardware RAID's vendor is totally independent from the >>> file system discussion. >>> >> Oh yeah it is. If you use hardware raid, you do not need barriers and >> can afford to turn it off for better performance or use LVM for that matter. >> > > Hi, this ist off list: Could you please explain me the LVM vs. barrier > thing? > > AFAIU, one should turn off write caches on HDs (in any case), and -- if > there's a BBU backed up RAID controller -- use this cache, but turn off > barriers. When does LVM come into play here? Thanks in advance! :) > > No, barriers are specifically to allow you to turn on write caches on HDs and not lose data. Before barriers, fsync/fsyncdata lied. They would return before data hit the platters. With barriers, fsync/fsyncdata will return only after data hit the platters. However, the dm layer does not support barriers so you need to turn write caches off if you care about data with lvm and you have no bbu cache to use. If you use a hardware raid card with bbu cache, you can use lvm without worrying and if not using lvm, you can (should in the case of XFS) turn off barriers. >>> I re-read XFS's FAQ on this issues, seems to me that we have to set up >>> two machines in the lab, one purely software RAID driven, and one with a >>> JBOD configured hardware RAID controller, and then benchmark and stress >>> testing the setup. >>> >> JBOD? You plan to use software raid with that? Why?! >> > > Mainly due to better manageability and monitoring. Honestly, all the > proprietary tools are not the best. > 3dm2 for 3ware was pretty decent whether http or cli... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
Timo Schoeler wrote: > thus Chan Chung Hang Christopher spake: > >> Timo Schoeler wrote: >> >>> thus Christopher Chan spake: >>> >>> >>>> Ian Forde wrote: >>>> >>>> >>>>> On Dec 7, 2009, at 10:30 AM, Florin Andrei >>>>> wrote: >>>>> >>>>> >>>>> >>>>>> John R Pierce wrote: >>>>>> >>>>>> >>>>>>> I've always avoided XFS because A) it wsan't supported natively in >>>>>>> RHEL >>>>>>> anyways, and B) I've heard far too many stories about catastrophic >>>>>>> loss >>>>>>> problems and day long FSCK sessions after power failures [1] or what >>>>>>> have you >>>>>>> >>>>>>> >>>>>> I've both heard about and experienced first-hand data loss (pretty >>>>>> severe actually, some incidents pretty recent) with XFS after power >>>>>> failure. It used to be great for performance (not so great now that >>>>>> Ext4 >>>>>> is on the rise), but reliability was never its strong point. The >>>>>> bias on >>>>>> this list is surprising and unjustified. >>>>>> >>>>>> >>>>> Given that I stated my experience with XFS, and my rationale for using >>>>> it in *my* production environment, I take exception to your calling >>>>> said experience unjustified. >>>>> >>>>> >>>>> >>>> The thing is that none of you ever stated how XFS was used. With >>>> hardware raid or software raid or lvm or memory disk... >>>> >>>> >>> Speaking for me (on Linux systems) on top of LVM on top of md. On IRIX >>> as it was intended. >>> >>> >>> >> That is a disaster combination for XFS even now. >> > > (Not company critical stuff -- just my 2nd workstation, the one to mess > around with; however, I didn't have problems yet -- what, of course, > should nobody invite do test it [on critical data]...!) > > Oh, nevermind. >> You mentioned some >> pretty hefty hardware in your other post... >> > > Which do you mean? > EMC2 storage... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
Timo Schoeler wrote: > thus Christopher Chan spake: > >> Ian Forde wrote: >> >>> On Dec 7, 2009, at 10:30 AM, Florin Andrei >>> wrote: >>> >>> John R Pierce wrote: > I've always avoided XFS because A) it wsan't supported natively in > RHEL > anyways, and B) I've heard far too many stories about catastrophic > loss > problems and day long FSCK sessions after power failures [1] or what > have you > I've both heard about and experienced first-hand data loss (pretty severe actually, some incidents pretty recent) with XFS after power failure. It used to be great for performance (not so great now that Ext4 is on the rise), but reliability was never its strong point. The bias on this list is surprising and unjustified. >>> Given that I stated my experience with XFS, and my rationale for using >>> it in *my* production environment, I take exception to your calling >>> said experience unjustified. >>> >>> >> The thing is that none of you ever stated how XFS was used. With >> hardware raid or software raid or lvm or memory disk... >> > > Speaking for me (on Linux systems) on top of LVM on top of md. On IRIX > as it was intended. > > That is a disaster combination for XFS even now. You mentioned some pretty hefty hardware in your other post... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
John R Pierce wrote: > Timo Schoeler wrote: > >> For enterprise environments my favorite FS is XFS, YMMV, though. >> >> > > I've always avoided XFS because A) it wsan't supported natively in RHEL > anyways, and B) I've heard far too many stories about catastrophic loss > problems and day long FSCK sessions after power failures [1] or what > have you > Fixed with the introduction of barriers for stuff that use fsync (therefore xfs on a partition, not lvm since dm does not support barriers) but then one probably uses hw raid with big bbu caches for xfs > is B) no longer an issue? > > I wanna know how come JFS/JFS2 (originally from IBM) isn't more popular > in the linux world? At least as implemented in AIX, its rock stable, > journaling, excellent performance, and handles both huge files and lots > of tiny files without blinking. jfs2 handles really huge file systems, > too. I really like how, in AIX, the VM and FS tools are coordinated, so > expanding and reorganizing file systems is trivial, nearly as simple as > Sun's ZFS. > yeah, love jfs. Using that in Ubuntu land. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
Jure Pečar wrote: > On Sat, 05 Dec 2009 10:48:56 -0800 > John R Pierce wrote: > > >> Timo Schoeler wrote: >> >>> For enterprise environments my favorite FS is XFS, YMMV, though. >>> >>> >> I've always avoided XFS because A) it wsan't supported natively in RHEL >> anyways, and B) I've heard far too many stories about catastrophic loss >> problems and day long FSCK sessions after power failures [1] or what >> have you >> >> is B) no longer an issue? >> > > You get horror stories about anything, depending on which people you ask. > For example, where reiserfs was supposed to eat data left and right some > years ago, I had 6 data losing crashes on ext3 and 0 with reiserfs. On same > machine, same disks, so same conditions. Go figure. > > Prior to 2.4.18 reiserfs was not in sync with the then ever changing vfs layer hence the data losses. It became stable after 2.4.18. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Is ext4 safe for a production server?
Miguel Medalha wrote: > I am about to install a new server running CentOS 5.4. The server will > contain pretty critical data that we can't afford to corrupt. > > I would like to benefit from the extra speed and features of a ext4 > filesystem but I don't have any experience with it. > Is there some member of the list who can enlighten me on whether ext4 is > mature enough to be used on a production server without too much risk? > > Some people have encountered data loss issues on Ubuntu (quite some time back and nothing reported recently) and ext4 support is not yet official in Centos5/RHEL5. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] recommend benchmarking SW
Alan McKay wrote: > Hey folks, > > We've got some new hardware and are trying to figure out what best to > do with it. Either run CentOS right on the bare metal, or > virtualize, or several combination options. Mainly looking at : > > - CentOS on bare metal > - CentOS on ESXi 4.0 with local disk > - CentOS on ESXi with 1 VM running Openfiler to serve disk to other VMs > > And want to benchmark these 3 scenarios > > So far all we have is a dd-based disk IO benchmark. > > What else can you all recommend. > > BTW, we also ideally want to try each of the above with a Postgres DB > as well (and once without) > > You can try fsbench which is not a generic benchmark. However, you mention Postgres DB so it may or may not be useful to you. fsbench simulates delivery to a maildir and simulates a single writer/reader to 16 writers/readers. Of course, it uses fsync calls unlike certain benchmarking software that do nothing of the sort like postmark. If you need a copy of fsbench, I have the original tarball that Bruce Guenter published. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] RAID 10 on Install?
Neil Aggarwal wrote: >> How can I RAID 10 on install? >> > > Does anyone know if this approach: > http://www.howtoforge.com/install-ubuntu-with-software-raid-10 > > Will work for CentOS? > Never tried the Centos LiveCD so I cannot say but manually creating the raid1 arrays and then striping them in a shell prior to partition does work since RH9. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] RAID 10 on Install?
ML wrote: > People went back and forth on the list saying that if a hardware > controller was out of the budget right now RAID 10 would be the best > solution. > That is raid1+0. raid10, under md, is something else different from raid1+0. > It seems that the installer wont let you create two RAID1 with the > same mount-pount and it looks like you have to specify one. I dont see > how to do this and I dont know how to make a custom installer for this. > You should mark those two mirrors as raid and then use them as members of a stripe array. If you cannot do that, then you will just have to manually do it on a shell (Alt+F2) and get the installer to rescan the raid devices. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] To all of the group
James Bensley wrote: > 2009/10/22 Chan Chung Hang Christopher > > >> Sorry, got mixed up. I thought he was talking about what he was doing >> for his company. Just kind of wary of people who go: Calling all Hackers >> but they actually mean Calling all Crackers >> > > > Now what are you on about, are you posting to the wrong thread per chance? > > Where in his post did he mention "Calling all Hackers"? Are you > hallucinatingon a Thursday? > > The weekend is too far away. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] To all of the group
James Bensley wrote: > Wait a minute, didn't someone just try and offer their help to the > community; > Where in their email did they mention cpanel? > Sorry, got mixed up. I thought he was talking about what he was doing for his company. Just kind of wary of people who go: Calling all Hackers but they actually mean Calling all Crackers > 2009/10/22 Christopher Chan > > >> DTS-Corp (Knowledgebase) wrote: >> >>> I am pretty much a newbie at CentOS, and Linux on client side, >>> >> Just in case it is not clear to you. cpanel is NOT Centos. It is a very >> badly modified version of Centos and we have nothing to do with it. >> Please take any issues you have with it back to Cpanel. >> > > > That doesn't say, Hi want some cpanel help, it says, "I would like to help > out occasionally by helping the web development crew in their endeavors". > > > > > ___ > CentOS mailing list > CentOS@centos.org > http://lists.centos.org/mailman/listinfo/centos > ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] sendmail question
Jerry Geis wrote: > Hi all, > > I have a local user account call "panel" on a machine. > When I use the mail command to manually send email to the panel account > it over 1 minute until that mail actually deposited in the mail account. > > What setting is that reduces this time? > > I changed /etc/sysconfig/sendmail the QUEUE=10s and that did not have > any effect. > > sendmail only queues if 1) the initial attempt suffered a temporary failure or 2) queueing mode was set. Otherwise sendmail will immediately attempt to deliver the mail. Check the headers of the test mail in question to find out where there was a latency. If you have a large queue already then that is your problem and setting QUEUE=10s will not help. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
Rainer Duffner wrote: > Chan Chung Hang Christopher schrieb: > >> I suspect so. After all, it is just seen as a disk as far as md is >> concerned and it will do the same normal thing if you unplugged a single >> disk from the array. >> >> > > > But the latency over the net is much higher. > Who knows if the kernel can handle this in all situations? > > Well, if the higher latency was a problem, I suspect that you will see its effects long before you even try to 'pull' a iscsi-target. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
Jonathan Moore wrote: > On Wed, Oct 21, 2009 at 7:51 AM, Les Mikesell wrote: > >> You can, if you connect the iscsi block devices into one machine that can >> combine them in one or more md raid devices, put a filesystem on them, and >> export via nfs and/or smb to the systems that want shared space. However, >> the >> > > If you did this, took a handful of machines, exported their storage > via iSCSI and had > a single server taking each of those iSCSI exported drives and > combining into a single > giant md device, would the theory of redundancy still hold? > > Say, I had 4 devices with 500 GB drives exported using iSCSI. If a > single larger server > took those four iSCSI export drives, and created one md RAID 5 device, > could a single > server be turned off, and just degrade the array until it was either > replaced entirely > or brought back online? > > I suspect so. After all, it is just seen as a disk as far as md is concerned and it will do the same normal thing if you unplugged a single disk from the array. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [OT] DHCP auth&auth software
Marko Vojinovic wrote: > Does anyone know about some free (as in beer, and maybe as in speech) > software > which would implement authentication and authorization of a user prior to > issuing a valid dhcp lease? > > I imagine the following scenario: someone walks into my office building with > a > laptop (a colleague, a visitor, a guest, whoever), and hooks up onto the > local > net (wired or wireless). The server detects an unknown MAC address, issues a > bogus dhcp lease which resolves all dns queries to a single internal web page > with a form the user is supposed to fill in and send. After he does so, an > administrator does a sanity check of the data the user provided, and grants > or > denies access. If access is granted, the user gets a new, unrestricted dhcp > lease, which provides him with a normal access to local network. > What about 802.11x authentication? If they are authenticated, they are assigned to the 'internal' vlan and if not, an alert or something else is triggered? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS 5.4? anyone?
Toby Bluhm wrote: > You Centos guys just aren't getting the message are you? > > We need to know EXACTLY what is going on with the release! None of this > "soon" crap will do. Please post a progress report on packages built, > isos transfered, server update progress by region, hours worked, > keystrokes typed, bathroom breaks, hours slept, family time taken. Bar > charts would be a nice touch. We need to know these things! Our very > lives hang upon this release. Strap a wireless webcam to your head for > god's sake and broadcast your every move. Verbalized every action. Quit > leaving us in the lurch! > > > Thank you > > > ROTFL. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] test
Janez Kosmrlj wrote: > testing mail delivery > > deliver failure: 550 Administrative Prohibition ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Asterisk and VOIP was Re: CentOS for non-tech user
>> When you say go voip, do you mean use sip for the stations only or also >> for the trunks? >> > > My experience (and the experience of those I know) is that SIP trunks > don't really work consistently. But, when I say I need to learn VOIP > I'm mostly talking about the station side. My goal is to learn enough > to build Asterisk boxes to replace key systems. I like the idea of > Asterisk because it can use standard trunks for critical lines and SIP > trunks for specialized purposes or overflow. (At least that's what I > *think* it can do.) > > Ah, well, if you want to keep the landlines, then yeah, I guess asterisk is the way to go. If your goal is to replace keyline systems, then asterisk definitely has that kind of support which, it appears, even Cisco's solution does not (from the mouth of Datacraft Asia personnel selling the school Cisco's voip solution). It can certainly do what you said about using standard trunks for critical lines (extra 'switch' to a plain pots phone on the trunk line in case you lose all power) and sip trunks for specialized purposes or overflow. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Asterisk and VOIP was Re: CentOS for non-tech user
>> You can get asterisk packages from rpmforge on Centos...but on Ubuntu >> you do not have to add an extra repository to get asterisk. >> > > Don't bother with that, go straight to the source! > http://packages.asterisk.org/ > These get updated rather quickly. > Ah, now that will definitely change my view of distro choice...no more waiting for latest packages. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
[CentOS] Asterisk and VOIP was Re: CentOS for non-tech user
Ron Blizzard wrote: > On Tue, Sep 29, 2009 at 3:09 PM, Tait Clarridge wrote: > > >> CentOS is great for server use and if you want to learn CentOS for use >> as a server, Fedora is a great place to start because they are both >> redhat based. Chances are that if you got something to work in Fedora, >> you can get it to work in CentOS (maybe with a few extra tweaks). >> > > I don't have any servers. I like CentOS on my desktop and my laptop > just because it's solid. It's also the Linux distribution of choice > for most Asterisk platforms -- which I intend to (eventually) learn. > (I'm a telephone tech, who is eventually going to have to go VOIP.) > > You can get asterisk packages from rpmforge on Centos...but on Ubuntu you do not have to add an extra repository to get asterisk. When you say go voip, do you mean use sip for the stations only or also for the trunks? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] CentOS for non-tech user
Niki Kovacs wrote: > Geoff Galitz a écrit : > > >> Ubuntu has the LTS releases, which are long term stable releases. They are >> supported for five years after release. >> >> > Ubuntu Long Term Support is three years for desktops and five for servers. > > In the last LTS version (8.04), half of the audio apps had no sound for > a month or so, until Ubuntu fixed the problems with Pulseaudio. At the > time, I had given Ubuntu 8.04 a shot in our public libraries and had > some very embarrassing moments. > +1. All my Ubuntu 8.04 trial boxes are now XP due to that. > Solution: stick with CentOS, rock-solid and *real* LTS. > > Yeah, if only I did not have to put Windows in a vm... Centos would have done the trick if it was just pure Linux. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Centos 5.3 Kernel panic with fuse and glusterfs.
Tom O'Connor wrote: > Matthew Miller wrote: > >> On Tue, Sep 15, 2009 at 03:24:52PM +0100, Tom O'Connor wrote: >> >> >>> If anyone has any ideas for further debugging, or other routes for >>> support. I'm running out of ideas. >>> >>> >> Enterprise Linux 5.4 with included official FUSE support seems like the next >> place to look. >> >> >> > Possibly, but i'd rather try and fix the problem without saying "oh > well, just upgrade to the latest release". It's quite a lot of effort > to fully upgrade a whole bunch of servers, but upgrading individual > packages would be far more realistic. > > Good luck tracking down the problem yourself then. The reason people use RHEL and therefore Centos is because much effort has been put into making sure the entire set of toolchains work well with each other. Upgrading a whole bunch of servers versus tracking down the problem and if you are successful, building your own rpms and your own repository, which one do you think will be more effort? Besides, 'upgrading to 5.4' is just that...upgrading individual packages. :-| ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] No envelope information
Luis campo wrote: > hi, > > have installed centos 4.7 > > We have installed qmail + simscan + vpopmail + SpamAssassin + clanAV > and when we send a mail from a particular domain, the following error leaves > us > > How about changing that combination of qmail + simscan to postfix + clamav-milter + spamass-milter? In any case, you would also want to look at the qmail logs...was it a bounce? > > > I wonder if this problem can be for Centos 4.7 or which would be the problem. > > Or the Microsoft SMTP service if you want to go this far. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] iptables
CentOS List wrote: > Hi, > > I have an existing iptables as follows:- > > # Firewall configuration written by system-config-securitylevel > # Manual customization of this file is not recommended. > *filter > :INPUT ACCEPT [0:0] > :FORWARD ACCEPT [0:0] > :OUTPUT ACCEPT [0:0] > :RH-Firewall-1-INPUT - [0:0] > -A INPUT -j RH-Firewall-1-INPUT > -A FORWARD -j RH-Firewall-1-INPUT > -A RH-Firewall-1-INPUT -i lo -j ACCEPT > -A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT > -A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 21 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 110 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 143 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 993 -j > ACCEPT > -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 995 -j > ACCEPT > -A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited > COMMIT > > How do add a redirect port 26 to 25. I had googled the net and notice that > the > syntax is different > > iptables -A INPUT -p tcp --dport 26 -j ACCEPT > iptables -A PREROUTING -t nat -p tcp --dport 26 -j REDIRECT --to-port 25 > > > *nat # Manipulate nat table :PREROUTING ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A PREROUTING -t nat -p tcp --dport 26 -j REDIRECT --to-port 25 COMMIT ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] [Found] CentOS is dead, long live CentOS
> However, we are NOT accepting monetary donations at this point. We will > not accept monetary donations until there is something in place where > more than one person has to approve any spending and some kind of > committee is in place to manage incoming and outgoing funds. > > ooh, ouch. A committee that is geographically located (or at least the approve spending part). I confess that I know nothing about how that kind of problem is dealt with though. Centos is becoming more and more like an organisation. Will a charter be set up too? (is there one? :-D) I see growing pains coming your way. Thanks for all the hard work. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
Joseph L. Casale wrote: >> Can I suggest ZFS on Solaris/OpenSolaris? Real breeze to setup. >> >> As for Linux, it has been a while but are there still two iscsi-target >> implementations? Has any one of them got into the mainline (Linux - not >> Redhat - although if Redhat will support one implementation I guess it >> does not really matter whether the mainline has it or not) kernel? >> > > Serious performance issues wrt to ZFS under iSCSI on Solaris/OpenSolaris > at the moment which require gobs of cash to fix. See rbourbon's post from > this thread: > http://opensolaris.org/jive/thread.jspa?threadID=111286&tstart=0 > > As for iSCSI on CentOS, I use iet versus tgt as the boxed instance leaves > lots to be done manually. Iet is actively developed by a some bright people > and is well tested/used and stable. I can assure iet works rock solid, I have > it exporting block devices to ESXi, nix and windows without ever missing a > beat. > Thanks for the update. > Also, according to http://kbase.redhat.com/faq/docs/DOC-15154 tgt is still > only a Technology Preview, so you wouldn't expect it to be complete yet. > > Did you install your iet from rpms or something then? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
> chan, I already have CentOS 5.3 setup, and we need to use this as far > as possible, due to some of the other software that we'll be using. > > See Joseph Casale's post then. It is not quite available on Centos. Roll your own is the name of the game. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
Rainer Duffner wrote: > Chan Chung Hang Christopher schrieb: > >> Rudi Ahlers wrote: >> >> >>> Has anyone succesfully setup, and used CentOS as an iSCSI server? I'm >>> trying to setup a server with 4x500GB HDD's, setup in RAID 10 to act >>> as an iSCSI server for a virtualization project, but I can't find a >>> decent howto on how to setup an iSCSI server using CentOS. >>> >>> I would like to setup something like Openfiler, but we also need todo >>> some other stuff that OpenFiler doesn't support, so I would prefer to >>> export some of the HDD space (about 500GB) as iSCSI LUN's >>> >>> >>> >>> >> Can I suggest ZFS on Solaris/OpenSolaris? Real breeze to setup. >> >> > > > Indeed. > But the problem is: this is a CentOS list and I'm afraid people just > don't want to hear an answer that involves installing a different OS. > Just like Windoze users don't want to hear about other OSs ;-) > > Even if there are no Centos solutions besides roll your own? Too bad. I am all for use the right tool for the job. The brand of the tool does not really matter. > >> As for Linux, it has been a while but are there still two iscsi-target >> implementations? Has any one of them got into the mainline (Linux - not >> Redhat - although if Redhat will support one implementation I guess it >> does not really matter whether the mainline has it or not) kernel? >> >> > > > CentOS inherits RedHat's implementation (don't know the details). > We use the iSCSI-initiator only, though, but that parts seems to work OK > for what we use it for. > > However, the OP is looking for a iscsi-target...which, if I am not wrong, does not quite exist yet in Centos/RHEL. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] using CentOS as an iSCSI server?
Rudi Ahlers wrote: > Has anyone succesfully setup, and used CentOS as an iSCSI server? I'm > trying to setup a server with 4x500GB HDD's, setup in RAID 10 to act > as an iSCSI server for a virtualization project, but I can't find a > decent howto on how to setup an iSCSI server using CentOS. > > I would like to setup something like Openfiler, but we also need todo > some other stuff that OpenFiler doesn't support, so I would prefer to > export some of the HDD space (about 500GB) as iSCSI LUN's > > Can I suggest ZFS on Solaris/OpenSolaris? Real breeze to setup. As for Linux, it has been a while but are there still two iscsi-target implementations? Has any one of them got into the mainline (Linux - not Redhat - although if Redhat will support one implementation I guess it does not really matter whether the mainline has it or not) kernel? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] looking for RAID 1+0 setup instructions?
I would NOT do that. You should like the md layer handle all things raid and let lvm do just volume management. >>> Your under the asumption that they are two different systems. >>> >>> >> You're under the assumption that they are not. >> > > http://en.m.wikipedia.org/wiki/Device_mapper > > If you want I can forward LXR references to MD and LVM into the device > mapper code or LKML references that talk about rewriting MD and LVM > for device mapper. > > > md can make use of dm to get devices for its use but it certainly does not just ask dm to create a raid1 device. md does the actually raiding itself. Not dm. >>> Md RAID and LVM are both interfaces to the device mapper system which >>> handles the LBA translation, duplication and parity calculation. >>> >>> >> Are they? Since when was md and dm the same thing? dm was added >> after md >> had had a long presence in the linux kernel...like since linux 2.0 >> > > Both MD RAID and LVM were rewritten to use the device mapper interface > to mapped block devices back around the arrival of 2.6. > > That does not equate to md and dm being the same thing. Like you say, 'TO USE' dm. When did that mean they are the same thing? >>> I have said it before, but I'll say it again, how much I wish md RAID >>> and LVM would merge to provide a single interface for creation of >>> volume groups that support different RAID levels. >>> >>> >>> >> Good luck with that. If key Linux developers diss the zfs approach and >> vouch for the multi-layer approach, I do not ever see md and dm >> merging. >> > > I'm not talking ZFS, I'm not talking about merging the file system, > just the RAID and logical volume manager which could make designing > installers and managing systems simpler. > > Good luck taking Neil Brown out then. http://lwn.net/Articles/169142/ and http://lwn.net/Articles/169140/ Get rid of Neil Brown and md will disappear. I think. > To create a raid1+0 array, you first create the mirrors and then you create a striped array that consists of the mirror devices. There is another raid10 module that does its own thing with regards to 'raid10', is not supported by the installer and does not necessarily behave like raid1+0. >>> Problem is the install program doesn't support setting up RAID10 or >>> layered MD devices. >>> >>> >> Oh? I have worked around it before even in the RH9 days. Just go into >> the shell (Hit F2), create what you want, go back to the installer. >> Are >> you so sure that anaconda does not support creating layered md >> devices? >> BTW, why are you talking about md devices now? I thought you said md >> and >> dm are the same? >> > > You know what, let me try just that today, I have a new install to do, > so I'll try pre-creating a RAID10 on install and report back. First > I'll try layered MD devices and then I'll try creating a RAID10 md > device and we'll see if it can even boot off them. > > Let me just point out that I never said you can boot off a raid1+0 device. I only said that you can create a raid1+0 device at install time. /boot will have to be on a raid1 device. The raid1+0 device can be used for other filesystems including root or as a physical volume. Forget raid10, that module is not even available at install time with Centos 4 IIRC. Not sure about Centos 5. >>> I would definitely avoid layered MD devices as it's more complicated >>> to resolve disk failures. >>> >>> >> Huh? >> >> I do not see what part of 'cat /proc/mdstat' will confuse you. It will >> always report which md device had a problem and it will report which >> device, be they md devices (rare) or disks. >> > > Having a complex setup is always more error prone to a simpler one. > Always. > > -_- Both are still multilayered...just different codepaths/tech. I do not see how lvm is simpler than md. >>> In my tests an LVM striped across two RAID1 devices gave the exact >>> same performance as a RAID10, but it gave the added benefit of >>> creating LVs with varying stripe segment sizes which is great for >>> varying workloads. >>> >> Now that is complicating things. Is the problem in the dm layer or in >> the md layer...yada, yada >> > > Not really, have multiple software or hardware RAID1s make a VG out of > them, then create LVs. One doesn't have to do anything special if it > isn't needed, but it's there and simple to do if you need to. Try > changing the segment size of an existing software or hardware array > when it's already setup. > Yeah, using lvm to stripe is certainly more convenient. > You know you really are an arrogant person that doesn't tolerate > anyone disagreeing with them. You are the embodyment of everything > people talk about when they talk about the Linux community's elist > attitude and I wish you would make at least a
Re: [CentOS] looking for RAID 1+0 setup instructions?
Miguel Medalha wrote: >>> You might be interested in this article: >>> >>> "Why is RAID 1+0 better than RAID 0+1?" >>> http://aput.net/~jheiss/raid10/ >>> >>> >>> >> The whole raid1+0 or raid0+1 argument was really only relevant in the >> days of pata when one disk dying on one channel might take out the other >> disk on the same channel or the controller. Now that we are using SATA, >> it is MOOT. >> > > No, it is not moot. Have you read the article? It has nothing to do with > PATA or SATA drives but with probabilities of failure under normal and > degraded state. > > "Mathematically, the difference is that the chance of system failure > with two drive failures in a RAID 0+1 system with two sets of drives is > (n/2)/(n - 1) where n is the total number of drives in the system. The > chance of system failure in a RAID 1+0 system with two drives per mirror > is 1/(n - 1). So, using the 8 drive systems shown in the diagrams, the > chance that losing a second drive would bring down the RAID system is > 4/7 with a RAID 0+1 system and 1/7 with a RAID 1+0 system." > Oh sorry, I have never argued about eight drive systems years ago (didn't have them then, too poor) and there is no argument about raid1+0 being the way to do it beyond four drives. It is too obvious that stripping three drives and then mirroring them is more risky than making three mirrors and then stripping them. Any argument then about whether one should do raid0+1 were really limited to those who had four drive systems and never thought beyond four drives. So it is really moot unless one ignores the obvious or fails to think. > "Another difference between the two RAID configurations is performance > when the system is in a degraded state, i.e. after it has lost one or > more drives but has not lost the right combination of drives to > completely fail." > > RAID 1+0 is still more secure." > Hear, hear. Man, I should leave the 90s back there. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] what is the best way to delete so many queue files?
MontyRee wrote: > Hello, all. > > > I found that so many unnessary queue files are saved at > /var/spool/clientmqueue/ directory. > How do you know they are unnecessary? > > > I tested two way to delete these files. > > 1. > # rm -rf /var/spool/clientmqueue/* > > 2. > # cd /var/spool/clientmqueue/ ; find . | xargs rm -fv > > But this makes a few load of the system and took too much time to delete. > > What is the best way to delete fast without too much load? > > service sendmail start? ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Samba Question
> Now the Designers groups should have rw rights for Projects and subfolders > > The draghtsmen should be able to upload only files (not folders) to > Final subfolder. They are not allowed to modify/delete anything > anywhere. They will not have any permission in project folder > > any ideas? > Further to Johnny's post, you can get what you want with ZFS. ZFS supports nfs4 acls which are quite close to NTFS acls. OpenSolaris is probably your next port of call if you do not want another Windows server. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] How to tell if I've been hacked?
>> Also processes you thinkk you DO recognize: >> Just for testing how alert my co-workers were, i had a program called >> "kswapd", just calculating prime-numbers... >> They never noticed. ;-) >> >> Without any preperation it's harder. No point in installing tripwire, >> activating apparmor/selinux afterwards. >> Those things should be done after a fresh installation. >> > > > Indeed. I once found a gdm binary that had been subverted. I'm certain > that would fly below the radar of many organizations. > > hence 'rpm -Va'. No such facility with dpkg so maybe not a common thing to do but this should be pretty much standard Redhat/Centos procedure for checking for corrupt/modified binaries/libraries. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] OT: Strange message in root e-mail possiablly hacked!!! Not sure??
> I didn't know that IPCOP could run on one that old. I have one like > that up in the attic, time to bring it back down. Before I upgraded to > 5.3, I was running 4.7 with FireStarter and did not have any troubles. > As soon as I get some sleep I will be looking in to setting it up. > > If it is a pure firewall/nat box then you may want to give OpenBSD a try. Expand your horizons a bit. I ran OpenBSD headless on a Pentium too but with a bit more RAM and diskless too. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
[CentOS] Centos - Chinese
A response I got from the local LUG here in Hong Kong to a post about translating the wiki articles into Chinese pointed me to the links below: http://www.centoschina.com/ http://apt.nc.hcc.edu.tw/web/student_server_centos/student_server_centos.html Posted just in case the Centos team has an issue with the first link. The site has a logo with 'CentOS' in it. ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] OT: Strange message in root e-mail possiablly hacked!!! Not sure??
>> So I started looking around in /var/log. I looked at my secure logs and >> saw nothing out of the ordinary. I looked in samba and found a log file >> 58.239.84.158.log. I opened it up and it said the following: >> >> [2009/08/15 06:31:34, 0] lib/access.c:check_access(327) >> Denied connection from (58.239.84.158) >> [2009/08/15 06:31:34, 1] smbd/process.c:process_smb(1062) >> Connection denied from 58.239.84.15 > I don't think you got hacked. You might want to check your firewall > settings though. It *looks* like your firewall is letting netbios > connections from off your LAN -- you should not be allowing this! > He can do better. Why is samba bound to an Internet facing interface at all? Unless you have a need to allow smb/cifs connections over the Internet, samba should never ever be allowed to bind to an interface with an Internet ip. > It does look like someone from 58.239.84.158 (SK Broadband Co Ltd in > Seoul) tried to check out your samba shares, but was denied access. > > Yea for tcp wrappers... ___ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
