[CentOS-virt] WinXP Xen guest: compare VNC vs RDP
I'm experimenting with using WinXP Xen guests as an alternative to upgrading workstations. The administrative advantages seem overwhelming. Please share thoughts about using VNC vs RDP for remote desktop connections. Please share any anecdotal information regarding user reactions and/or implementation issues. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Joseph L. Casale", Wednesday, April 22, 2009 4:23 PM >> I'm experimenting with using WinXP Xen guests as an alternative to >>upgrading workstations. The administrative advantages seem overwhelming. > > Using the beta opensource parvirt drivers? Performance would be > unacceptable > otherwise. On that note, my environment would not permit the unstable > nature > of such an exercise... Actually, no. I'm using the fully virtualized guest. My test virtual machine server is a Dell PowerEdge 2900 with dual-core Xeon with stock CentOS 5. It only runs at 2Ghz, but I'm finding acceptable performance for the standard business applications that my users will run. The system can go up to 2x4 core Xeons running at 3.33Ghz or something. Ram can go up to 48G and it has the option of 2 banks of 4 slots for hotswap hardware RAID. I'm hoping to be able to run about 12 virtual XP boxes on a 2900 with 8 x 3Ghz cores and 16G RAM. My current workstations are 1.6Ghz Celerons with 512M to 1G RAM. They are only running Outlook Express, Internet Explorer and a couple of proprietary applications. If paravirtualization drivers for WinXP ever become stable, that'd improve performance and probably increase the number of WinXP VM's quite substantially. >> Please share thoughts about using VNC vs RDP for remote desktop >>connections. > > RDP will be way faster, not to mention using vnc provides access to the > console which won't have video performance needed. Have you done any real world like testing? My experience seems to indicate VNC being faster on a LAN. Since the console is being redirected in the host, rather than the guest, it seems to demand less processing power. Also, turning off remote access in the guest loads less software. Since the host supports the VNC console access, it becomes available much sooner than WinXP get termserv up. >> Please share any anecdotal information regarding user reactions and/or >>implementation issues. > > There's nothing cooler than Xen, but IMHO opinion I would be using > something > a bit more stable for Windows guests, it's not the right tool for >this< > job > as far as I am concerned. > > YMMV I've got some local databases with chatty Windows clients that becomes unuseable across the WAN and doesn't play well with MS Terminal Services. Rather than have a stack of physical WinXP machines for my remote users, I'm looking at virtualization. VMWare gets too expensive, too fast. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Julian Price", Wednesday, April 22, 2009 3:46 PM > I use RDP because it allows copy & paste of text between the local and > remote machines. VNC does not, unless I've just not got it set up right. > > - Julian Most of my users are not sophisticated enough to handle mixing remote and local modes. I'm expecting to turn the remote machine into a thin client equivalent (enabling me to move the WinXP license to the VM). This seems to reduce some of my potential support issues. I'm currently experimenting with Thinstation (thinstation.net). There are a couple of issues with it, like sound, but I'm leaving those issues for later. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Manuel Wolfshant", Wednesday, April 22, 2009 4:58 PM > ... > - XP was MUCH faster in Xen, compared to real hardware (!) I've been pretty happy with the performance, as well. > - RDP beats VNC in terms of speed any time, any place. I cannot evaluate > precisely the factor, but empirically I'd say that in our conditions > (WAN link, 6 Mbps upstream link on one site shared with other projects, > 100 Mbps on the other site) it was at least 2-3 times faster. Interesting. Thanks. > - rdesktop ( the linux app) is really cool, as it allows you to > share/transfer local resources to the remote XP session (for instance > you can map a local directory as a remote networked disk, without the > hassle of passing via Network Neigh.). VNC forces you to either > explicitly map such resources (hence you would also need something like > samba on the linux side) or use scp. Either way, I won't be having local resources. Trying to keep it simple. > - the only problem with RDP is that by default Windows limits the number > of simultaneous connections. but patches do exist (which violate the > licensing/usage terms, so beware). I am interested in the multiple connections allowed with VNC for support type console sharing. When connected with RDP, the console of the VM has a login screen, so you can't use VNC to the console at the same time as a RDP connection... > As of implementations issues .. I had two (or should I say three?) > problems: > - one is detailed in an older thread on this list ( look for "Using the > parallel port from domU", 02/02/2009). My printers are all network printers, yay! > - second is due to Xen creating a large file with the same size as the > disk given to the VM. I would have believed that sparse files would have > been used, but df showed the opposite. I have seen 20 GB of space > allocated, despite XP only using less than 5. I think I've got the VM's setup with sparse files. An ls shows the 10GB size, but df doesn't show all the space in use. However, this is a minor issue. The virtual server I'm looking at has the capacity for a couple of terabytes of hardware RAID storage. > - last issue did not occur with stock Xen but with v3.3: Java inside the > VM went nuts and starting consuming 99% of the processor.. while doing > nothing. Once we reverted to stock Xen from C5.2, it went back to normal. I'm going to be trying to avoid using other than stock Xen. This has got to reproducible and supportable. I'm thinking of setting up a local repo to prevent automatic updates from breaking anything. Thanks for all of the information. Makes me wonder what happened to eliminate the need... ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Manuel Wolfshant", Wednesday, April 22, 2009 5:42 PM > Well, if you can implement a LTSP-like solution, good for you. In my > case all users already had local linux workstations running C5, the XP > was needed only for a couple of proprietary applications and for a > limited period of time. The problem came from the fact that despite > using what I call pretty decent hw, most of the users did not have > hardware capable of doing full virt but we had to start the project > really FAST ( The software supplier informed me that the proprietary > applications cannot run on linux the very day the project started, > despite doing 3 months of preparations for the project). Basically I had > no choice but create VMs on a server with spare resources (which > happened to be in another city than the users). Your use case is > different :) Yes. All of my current users have WinXP. I am merely moving their workstations into VM's in order to increase their processing power. >> I am interested in the multiple connections allowed with VNC for >> support >> type console sharing. When connected with RDP, the console of the VM has >> a >> login screen, so you can't use VNC to the console at the same time as a >> RDP >> connection... >> > It's not really like you describe it. With the proper patch, several > different RDP users can share the VM, just as an 2003 server would do > for more money. In our case, this was important because - at least in > the beginning of the project - the number of simultaneous users exceeded > the number of available VMs > As of VNC sharing the console .. I am not sure what are you speaking > about. As far as I know, VNC is quite reluctant to share a single > desktop with several users, unless the connections are R/O. And in a LAN > the speed is acceptable, but via remote links VNC quickly becomes > "unpleasant". If you go the VNC way, I strongly suggest to examine NX > instead. Yes. Read-only secondary connections for support. Since this is a long term solution (permanent), I get to design for sufficient resources. > I have only networked printers, too, but in this case it was not about a > printer but a hardware toy (ASIC development board). I have one device in several of my offices that the vendor specifies a brain-dead serial cable. I'm expecting this to be my only hardware hurdle. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Joseph L. Casale", Wednesday, April 22, 2009 7:28 PM >> I am interested in the multiple connections allowed with VNC for support >>type console sharing. When connected with RDP, the console of the VM has >>a >>login screen, so you can't use VNC to the console at the same time as a >>RDP >>connection... > > Remote Assistance parallels the behavior you're after with RDP. Yup. I'm currently using Remote Assistance with my WinXP users. This requires WinXP Pro, but since pro was required for other things, we already use it. The downside of Remote Assistance is that the user has to be able to create a request. Sometimes, I have to take over their computers with RDP, create a request, let them log back in, then I accept the request on my machine. The other downside is that, afaik, Remote Assistance request can only be accepted by a Windows OS. This is what keeps me from moving many of my workstations away from MS. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Christopher G. Stach II", Wednesday, April 22, 2009 5:31 PM > It's a really bad idea to allow connections into dom0 from anything other > than an administrative network and for administrative purposes. RDP is > generally a better solution than anything else, anyway. I don't think anybody disagrees with this, in theory. But I'm not going to kill the project if the expected performance is less than required using RDP and acceptable using VNC. Since I'll have a hot spare and the virtual machine server is relatively easy to rebuild, I'm going to have to allow for it as a Plan B. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] WinXP Xen guest: compare VNC vs RDP
From: "Christopher G. Stach II", Wednesday, April 22, 2009 5:39 PM > You can handle this with Thinstation and many other thin clients. Thinstation is exactly what I'm currently using. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] How to pass messages from dom0 to domU??
From: David Knierim, Wednesday, July 22, 2009 3:18 PM >I apologize if this is a newbie question, but I have been unable to work >out how to do this. >I am adding code to my installation on dom0 (running CentOS 5.3) to monitor >for hardware faults. If there is an issue, I want to propagate the status >to all of the domUs (running CentOS 4.x or CentOS 5) running on the host. >What are my options to do this?? I would use shared file space. Maybe an NFS share that all machines could access... That way it is not restricted to virtual machines running on that server. If you expanded to 2 servers for increased capacity or fault tolerance, you would not have to redesign it. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] VNC not connecting
From: "Neil Aggarwal", Tuesday, October 20, 2009 12:35 PM > ... > When I do that, I get this error: > > (virt-viewer:3083): Gtk-WARNING **: cannot open display: > Domain installation still in progress. You can reconnect to > the console to complete the installation process. > ... include the --noautoconsole option on your virt-install command > ... > Next, I tried to connect TightVNC viewer from my > Windows XP laptop. I entered 192.168.2.200:3 > as the server and tried to connect, but that failed. > ... Did you open the VNC port in iptables in dom0? Did you add (vnc-listen '0.0.0.0') in /etc/xen/xend-config.sxp? Please consider adding a vncpasswd config item in your xend-config.sxp ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Virsh shutdown all command?
From: "Neil Aggarwal", Thursday, November 12, 2009 5:34 PM > Is there a command in virsh to shutdown all domains? > I can do one at a time, but that is untenable for a large > number of domains. I use a script to shutdown my domains. I am not always happy with stopping the service, which is supposed to have the effect of stopping the virtual machines. I use xm and do other things, including rebooting my MS Windows XP VM's on a schedule, but here's the piece that just does a shutdown on running VM's. I'm sure my script isn't very efficient and I'd appreciate any polite, constructive suggestions. Also, since I've pulled it out of a script and modified it on the fly for virsh, there might be bugs. The debug environment var is use for verbosity. The fake environment variable is used for 'faking' the run. Setting both while debugging might be a good idea unless you are using a test system without any production virtual machines. -- #!/bin/bash # file: /usr/local/sbin/vm-shutdown # Description: shutdown active virtual machines # Get list of active virtual machines vmList="`virsh list | ( while read vmID vmName vmStatus do if [ -n "$vmName" -a "$vmName" != "Name" -a "$vmName" != "Domain-0" ] then [ -z "$vmList" ] && vmList="$vmName" || vmList="$vmList $vmName" fi done echo $vmList )`" # check there are some active VM's if [ -n "$vmList" ]; then # Shutdown VM's with verification for vmName in $vmList do # send initial request [ -n "$debug" ] && echo -n "Attempting to shutdown $vmName " [ -z "$fake" ] && virsh shutdown $vmName # wait a limited time for the VM to be not running count=300 while ( virsh list | grep $vmName >/dev/null ) && [ count -gt 0 ] do sleep 1 let count=count-1 [ -n "$debug" ] && echo -n "." done # report current status ( virsh list | grep $vmName >/dev/null ) && echo " failed!" || echo " down." # if still running, destroy it if ( virsh list | grep $vmName >/dev/null ) then [ -n "$debug" ] && echo -n "Attempting to destroy $vmName " [ -z "$fake" ] && virsh destroy $vmName # wait a limited time for the VM to be not running count=60 while ( virsh list | grep $vmName >/dev/null ) && [ count -gt 0 ] do sleep 1 let count=count-1 [ -n "$debug" ] && echo -n "." done # report current status ( virsh list | grep $vmName >/dev/null ) && echo " failed!" || echo " down." fi fi -- over engineering and over analysing for 3 decades... or is it over analysing and over engineering... ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Xen domU default gateway missing/ARP table full
I was slightly confused about this thread until I realized you were using static IP config on your VM's... Why do people do that? I have an extra step of picking up the HW address (or setting the HW address when creating the VM) and putting it into my dhcp configuration, but then I have all of my hosts in a single file and I can change the network configuration of my whole network in a single place. I realize that my DHCP server becomes a single point of failure, but with a reasonably long retrain time the DHCP server going down won't effect any workstations for as much as several hours (as long as nothing reboots). Also, there are ways of having fault tolerance with DHCP, the easiest would be to have a non running VM with a copy of the data. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Virsh shutdown all command?
From: "Torkil Zachariassen", Monday, November 23, 2009 5:35 AM > On Fri, 2009-11-13 at 10:47 -0700, Ed Heron wrote: >> From: "Neil Aggarwal", Thursday, November 12, 2009 5:34 PM >> >> > Is there a command in virsh to shutdown all domains? > >> I'm sure my script isn't very efficient and I'd >> appreciate any polite, constructive suggestions. Also, since I've pulled >> it >> out of a script and modified it on the fly for virsh, there might be >> bugs. > > Fixed a bug or two and made some hoovering. > All the best. > ...torkil... Shall I assume it is useful? I was expecting someone to ask why I was getting a list of VM's separately from the section that did the shutdown... I did that because my script does an action on either a default list of VM's (stop/shutdown uses list of active VM's, start uses list in /etc/xen/auto, reboot uses list in /etc/xen/reboot) or the list from the command line. I link vm-stop and vm-start to vm-reboot and check $0 when it runs. Should we expand the script and include the other options? Maybe rename it to virt-start, virt-stop, virt-reboot? (to complement virt-install) Or, call it virt-cntl and have options like --reboot, --stop & --start? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] kickstart + domU for static IP
From: "john maclean", Tuesday, April 06, 2010 4:11 AM > I've set up a local webserver to store kickstart files for domUs. All > parameters are respected apart from the network settings. DomU always > gets DHCP. Can any one help to unwrap this one? Does one add hostname, > ip, netmask and gateway values to the /etc/xen/blah.cfg file? > > # domU kickstart file # > ... > > # sudo cat /etc/xen/dns1.cfg > ... > -- > John Maclean > 07739 171 531 > MSc (DIC) > > Enterprise Linux Systems Engineer It's not quite clear to me what your process for creating the DomU is, but I think you're creating the xen config file by hand then running xm create ? I'm not sure when you are having the IP issue. If during the installation process, anaconda has to initialize eth0 before it can get access to the kickstart file, so it must use DHCP. After some discussion with Russ some time ago, he convinced me that in most cases, virt-install is your friend. I use virt-install (specifying a mac address) to create my virtual machines, which sets up a boot partition, just like a physical machine, so my extra parameters go into the VM's /boot/grub/grub.conf file. I assign static IP addresses with DHCP during the install process and also set the IP address in the kickstart file (if it is a server). I like that the VM's config is mostly internal to the virtual disk image. I don't have a problem controlling my IP addresses. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] kickstart + domU for static IP
From: "Ed Heron", Wednesday, April 07, 2010 9:11 AM > ... and also set the IP address in the kickstart file (if it > is a server). ... I should add that I set the static IP address from %post using: # Configure eth0 file="/etc/sysconfig/network-scripts/ifcfg-eth0" sed --in-place "s/^\(BOOTPROTO=.*\)$/#\1/" $file sed --in-place "s/^\(DHCPCLASS=.*\)$/#\1/" $file cat <>$file BOOTPROTO=none IPADDR=xxx.xxx.xxx.xxx NETMASK=xxx.xxx.xxx.xxx GATEWAY=xxx.xxx.xxx.xxx EOF I do it this way, because I really don't care what the IP address is during install. I want the IP address to be set during the next boot. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
[CentOS-virt] virt-manager connect to remote virtual server xen+ssh
I don't usually install a graphical environment on my servers, so I don't usually use virt-manager. However, I recently put CentOS 5 on my Dell Latitude D820. It has hardware virtualization support, 4G RAM and a 500G HD, so I can carry a virtualization lab around with me. I found the trick of getting a non-active xen VM to show up in virt-manager's list by using virsh edit and changing the amount of RAM, so that was cool. I'm trying to use virt-manager to manager my other xen based virtualization servers, but I'm unable to successfully connect to them. I am able to connect to the other servers with virsh --connect=xen+ssh://vsrv/, though, so I'm assuming it has something to do with virt-manager. I haven't, yet, found any debug mode, so I'm hoping someone on the list has some suggestions for me. Please, give me some hints as to where to go next in trouble shooting virt-manager connecting to a non-local xen server. Is there a debug mode that I'm missing? Ed Heron ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Move Xen Image to Another Server
On Tue, 2010-06-15 at 00:17 +0800, Wendy William wrote: > after RESTART server then I can not ping to Dom-U. Remember that if you want the domain to start at boot, you must link the cfg file in /etc/xen/auto/ ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] new to xen - got questions, please
On Wed, 2010-06-16 at 12:11 -0400, Steve Campbell wrote: > I just installed Centos 5.5 with the xen kernel on an older machine. It > has Xeon processors and a 700 Mhz processor speed, so I realize I must > use para-virtualized guests. Reading the Centos/RH Virtualization Guide > gives examples of the process of installing guest hosts, but it only > lists installing Windows as a fully-virtualized host. > > Is that because they only showed those types of examples or is it that > Windows hosts can't be para-virtualized? I'm not sure how far the para-virtualized drivers for MS Windows (XP?) have gotten. I would only install a MS Windows XP virtual machine as a fully virtualized guest, at this time. I haven't begun to work with Vista or 7. If I were restricted to the older machine, I'd explore using VMWare. The bare metal version should be comparable to XEN performance, but the free version is restricted as far as the number (3?) of virtual machines that can be run. It'll virtualize MS Windows guests on older hardware. Evaluate why you are using virtual machines... If this is an evaluation period, the older equipment is OK; Explore the alternatives. If this is a production machine, you'll be happier with a newer computer. > Secondly, what's the normal what to install a Centos guest when it comes > to defining the installation media (it lists HTTP, FTP, or NFS). This > machine only has a CD drive, so I'm a little confused about the best way > to handle this since the Centos installation now consists of 6 CDs. A > brief explanation would be handy. Download the DVD and put it in /var/lib/xen/images/, set it as a virtual optical drive. The process is slightly different depending on whether you are creating the virtual machine using a xen config file, virt-install (command line) or virt-manager (gui). ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] new to xen - got questions, please
On Wed, 2010-06-16 at 12:40 -0700, Drew wrote: > The free ESXi can virtualize more then three guests. The limitations > imposed on the free license revolve more around advanced capabilities > within the suite. Things like vMotion (automatic guest migration > between hosts), High Availability, etc are disabled. > > http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006543 > > Down at the bottom you'll find the edition comparatives. Thanks for that. Obviously, I am not entirely informed with respect to ESXi. I've used VMWare Server on Linux and MS Windows (XP, 2003) and, while it worked, I wasn't satisfied with the performance for a production environment. Due to my limited budget, I've been 'scared off' from setting up a ESXi testing environment, though it is still 'on my list of things to do'. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] VMWare 4.1 and CentOS
On Sun, 2010-10-24 at 16:03 -0500, Drew Kollasch wrote: > Is there any known issues when trying to run CentOS (x86 or x64) on a > fresh install of vmware 4.1? > > Details as to why I am asking are here in the CentOS > forums: > https://www.centos.org/modules/newbb/viewtopic.php?viewmode=flat&order=DESC&topic_id=28521&forum=39 > > Thanks! > -Drew Reading that thread... Is the kernel panic during install or during first boot? Assuming first boot, there are a few options. 1. Use an older install disc. This was the suggested resolution. 2. Use a kickstart file to update during install (%post), before first boot. 3. Use the install disc as a rescue disc to update the system after install, before first boot. I like this option for the simplicity in a single instance install. 4. Setup a local repository, with updates, and install from there using the net install disc. I like this option for multiple installs. I'm heading in this direction except with PXE instead of physical discs. If while booting the install disc, 1. See option 1 in previous section. 2. Create your own updated install disc. This option has very little to recommend it as it is significant effort for little gain. The pro is that you will have a very good understanding of how the install disc is put together. Also, that issue appears to be AMD related? If you have another virt server that uses Intel, you could create the VM, install, update and then move it. All in all, using a CentOS 5.4 install disc and upgrading seems to be the simplest for your one off. That should be possible with AsteriskNow if you use an older disc of theirs. As far as Asterisk goes, I don't restrict myself to VoIP, due to 911 requirements. In the event of power failure or Internet issue, my POTS line works more reliably. By having a UPS on my Asterisk system and PoE for my phones in conjunction with a POTS line, I have a system that is more survivable during external issues. Since I run independent VoIP and data networks, it makes sense on several levels to maintain my primary Asterisk system on bare metal. Though, in the event of failure, I have no problem running the backup on my virt server. I use Elastix, which is also CentOS 5 based. I modify the kickstart file to do updates at the end of %post. I use PXE, but it should be straightforward to modify the disc image before burning. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] New to virtualization - can't use more than one CD when installing a new VM
On Mon, 2011-06-27 at 16:02 -0400, Steve Campbell wrote: > ... > I'm trying to install my first VM using Centos 5.5 as the host as well > as the VM OS. It starts fine using VMM, but when it asks for the second > disk of 8 CDs, the first one isn't ejected, although unmounted because I > can open the tray, and won't recognize that the second CD is inserted. > ... Why not use a DVD image in /var/lib/xen/images? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] New to virtualization - can't use more than one CD when installing a new VM
On Mon, 2011-06-27 at 15:37 -0600, Ed Heron wrote: > On Mon, 2011-06-27 at 16:02 -0400, Steve Campbell wrote: > > ... > > I'm trying to install my first VM using Centos 5.5 as the host as well > > as the VM OS. It starts fine using VMM, but when it asks for the second > > disk of 8 CDs, the first one isn't ejected, although unmounted because I > > can open the tray, and won't recognize that the second CD is inserted. > > ... > > Why not use a DVD image in /var/lib/xen/images? Or better, setup a local mirror using http://wiki.centos.org/HowTos/CreateLocalMirror Then create your CentOS DomU with something like: virt-install --name= --vnc --vncport=59xx --noautoconsole --paravirt --ram=512 --vcpus=1 --network=bridge: --file= --location= --os-type=linux --os-variant=rhel5 --extra-args="xencons=tty noipv6" ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Now on to creation of disk images
On Tue, 2011-06-28 at 09:30 -0400, Steve Campbell wrote: > Mr. Heron was so kind to make a suggestion that I should use disk images > to install VMs. Upon further thought, I kinda like the idea. So I > re-read the manual and google a little, and discover I still don't know > what should be in these disk images. > > Should I copy the contents of the CDs to a file or what? I've got a test > server at the moment with Centos 5.5 and xen installed as the host OS, > but have just downloaded the 5.6 CD ISOs along with the DVD ISO, so > I'll use 5.6 for my VMs. I've read about how I can create an image from > something that already exists. > > Again, any clarity would be appreciated. Just put the ISO's in /var/lib/xen/images and point at them. If you didn't download the discs, you can rip them using: dd if=/dev/ of=/var/lib/xen/images/ For example, if ripping the first 5.6 CD... dd if=/dev/hdc of=/var/lib/xen/images/CentOS-5.6-i386-d1.iso I generally rip a disc multiple times and then do a file compare to make sure I've got a reasonable chance of having an undamaged copy. Keep in mind that it isn't as easy to change discs when you are using images on a paravirtual machine. I still recommend setting up a local repository as a much better solution because it allows you to take a snapshot so multiple installs use the exact same versions of everything. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Now on to creation of disk images
On Tue, 2011-06-28 at 13:35 -0400, Steve Campbell wrote: > Ed, > > What do you mean by "ripping"? As far as the dd command you mentioned, > it appears that the ISO file itself is copied to the folder, not the > expanded iso-into-files themselves. Is this correct? If so, that's just > too easy. > > Thanks for your kind assistance. > > steve campbell Yes. By 'ripping', I'm referring to pulling the data from a disc. In this case, I'm using the dd command to create a file with the raw data from the disc. That raw data file can then be used to burn another disc or provided to a virtual machine as a virtual disc. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Suggestions to improve this minimal kickstart config for CentOS 6?
On Tue, 2011-07-19 at 12:36 -0400, Kartik Subbarao wrote: > I've come up with the following kickstart config (see below) for > deploying a minimal CentOS 6 VM. It takes about 460MB. I'm assuming that > all of the -firmware RPMs aren't needed for a VM installation, so I > removed them. Also removed as many selinux packages as possible since I > don't need that. > > I was wondering whether anyone could offer any further suggestions on > minimizing the disk usage of the VM image. > ... > > > > ... > rootpw admin123 I use the --iscrypted option so people can't easily see my default root password. An easy method of viewing the command is looking at /root/anaconda-ks.cfg (at least it was in 5) after install. For setting unique initial root passwords, there is a method for creating it on the command line. > ... > # Repositories > url --url="http://mirrors.kernel.org/centos/6.0/os/x86_64/"; > Shouldn't we encourage the creation of a local mirror? Installs are much faster. Also, with local mirrors, you can snapshot the repo. This allows for testing updates before pushing them to your live servers. > ... I create ks files for many of my CentOS and CentOS derived (Elastix) boxes. Backups take less space when you only save data. Routers are great for this as they rarely change (except possibly for firewall rules). With PXE boot, I can rebuild a router in 10 minutes. Also handy if the router hardware fails (I'm using old PCs). An on-site user without any Linux knowledge can install a replacement router (or re-install an existing router if it is suspected to be compromised) in little time. As long as the ks file is used as the master configuration where changes are made and the router re-installed to make them active, you don't get into a position where a change is lost if the hardware fails. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] compress raw image
On Thu, 2011-08-04 at 16:35 +0200, Rainer Traut wrote: > Hi, > > I need to transfer a local raw image to another datacenter. > Is there a way to achieve good compression of this image, I heard of > tools overwriting unused space with zeros. Is this a good idea? > > It's an W2k8 image/NTFS. > > Thx > Rainer I'd use dd if= | bzip2 | ssh @ "bunzip2 | dd of=" or something similar. I'd then do ssh @ "md5sum " ; md5sum to give myself some reassurance that they were the same. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] lvm and kvm
On Mon, 2011-08-15 at 15:54 -0400, James B. Byrne wrote: > I am performing some configuration testing on a kvm host. When > installing a guest operating system is it advisable to place each > instance in a separate lv or better to accept the default and store > them on the root file system? I think you are asking LV based or file based guest storage. I vote for LV on the host. > Respecting lvm, does one configure lvs in a virtual server to take > space from the main vg or does one allocate lv space from inside > that allocated to the virtual instance? Is it even considered > advisable to use lvs with virtual guests? > ... It seems that you are asking whether to use (1) multiple host LV's to keep different partitions on different virtual disks, (2) a single host LV with nested LVM or (3) a single host LV with traditional partitioning... I use Xen, but if we treat this as a philosophical discussion, that probably doesn't matter. I like option 1 (multiple host LVs) for the flexibility it gives, but I don't like the large number of LVs on the host. I don't like option 2 (nested LVM) due to the difficulties of resizing guest PV. Option 3 (single host LV, raw guest partitions) keeps the number of host LVs lower, but only the last guest partition is easily resized. If you can accept the number of LVs or you need to resize your partitions frequently, I'd recommend option 1. I have gravitated to option 3 because I find I don't need to resize my guest virtual disks very often. MS Windows uses a single partition, so those VMs are simple. On my Linux VMs, I normally only need to resize either the var partition or the home partition depending on the machine's function, but not both, so I put that partition last. I recommend against using LVM within a VM. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] P2V of NEtware 3.12 working server to Centos >=5.x
On Tue, 2011-09-06 at 23:20 +0530, Rajagopal Swaminathan wrote: > Greetings, > > I would be grateful if anybody can kindly give a pointer to port a > Working netware 3.12 server using Centos >=5.x KVM howto? > There are so many variables that aren't mentioned... Do you currently have a CentOS box running KVM? If no, this is your first step. Since a virtual server can run multiple virtual machines, it is only useful if you intend to run multiple virtual machines. What does your Netware server currently do? If it does more than file and print services, you will have to determine how you would replace those other services. Netware 3 defaulted to using the IPX protocol for sharing file and print services. Are you still using IPX? If so, you are looking at a significant network reconfiguration. Netware 3 could integrate with a variety of client OS's; Unix, DOS, OS/2 and MS windows. What method is your server using to provide services? There might be lots of changes to client setup and software, but look at Samba. It can be setup with a workgroup for file and print services that might be sufficiently similar to how you are currently working. The differences between a physical CentOS server with Samba and a virtualized CentOS server running Samba are minimal and don't directly effect Samba configuration. There might not be a simple document or a series of simple documents to point you at. It might be easier to setup a new network with the new server and a few clients to work out the concepts and any issues you're going to run into. Once you have everything working well on your new network, do a last copy of current data and migrate all your workstations. I hope I'm mentioning use cases that don't apply. Hopefully, you already have significant CentOS experience. Hopefully, this might be a simple file and print server migration for MS Windows clients. The broad wording of your request might just be language barrier. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] P2V of NEtware 3.12 working server to Centos >=5.x
On Wed, 2011-09-07 at 19:54 +0530, Rajagopal Swaminathan wrote: > Greetings, > > On Wed, Sep 7, 2011 at 12:34 AM, Ed Heron wrote: > > > > On Tue, 2011-09-06 at 23:20 +0530, Rajagopal Swaminathan wrote: > > > > There are so many variables that aren't mentioned... > > > > Do you currently have a CentOS box running KVM? > > I have used centos with KVM,brctrl etc. > > > > > > > What does your Netware server currently do? > > Just just pure and simple file storage. The worst part of it is The > client has to be a DOS6.22 with some custom ISA base hardware. > > > Netware 3 defaulted to using the IPX protocol for sharing file and > > print services. Are you still using IPX? If so, you are looking at a > > significant network reconfiguration. > > > > Indeed. with 802.3 frame etc :) > > > There might be lots of changes to client setup and software, > > > but look at Samba. It can be setup with a workgroup for file and print > > Now, How to access Samba with Dos 6.22? :p There was a workgroup client for DOS that used TCP/IP. I can't vouch for it's working, but try ftp://ftp.microsoft.com/BusSys/Clients/MSCLIENT/ > One main thought that first came to my mind is about the NIC Driver > under KVM I do understand that the Centos5 can present it as different > types of NIC (Intel, Realtek etc.) > > I am investigating it further. > > > Hopefully, you already have significant CentOS experience. > > Last 6 years or so I have worked only Fedora/Centos/RHEL. Since then I > have tried avoid taking calls windows etc. > > But this call I took because I have significant experience in netware > too about 10 years 2.2 to 4.10 with NDS etc I, also, supported Netware 2 and 3. I avoided 4 due to NDS and the availability of Samba. It was a big deal when the Internet was gaining momentum. At first, we had multiple protocols and multi-protocol routers. My memory is vague but I'm pretty sure Netware 3 could run NetBIOS on a TCP/IP stack. > > > The broad wording of your request might just be language barrier. > > I realised that. > > I will experiment further share my experience sometime later. > So, are you looking to move your existing Netware 3 server into a virtual environment? Or, are you looking to replace an existing Netware 3 server with a CentOS equivalent? I would suggest setting up a CentOS server with Samba and convert the DOS network stack, if you can. Samba appears to be much more supportable, currently. Take a look at the FreeDOS project, too, as an example of getting DOS to work in a more recent environment. The biggest concern (after getting the clients to talk to Samba) is that there have been a few choices made in Samba with respect to file sharing/locking mechanisms. With old software, you may have to look at those settings. If you attempt to virtualize Netware, you may run into issues, though it'd be an interesting exercise. I don't know if a Linux hypervisor will handle IPX packets without IPX support installed. You might need to check for an ipx kernel module. Also, my version of Virtual Machine Manager running on CentOS 5 with Xen doesn't give me any sort of Netware OS option when creating a new virtual machine, so you'll probably have to play with settings. I google'd netware virtual machine and saw a few links to virtualizing Netware 3 under VMWare which might give you some insights. Either way, do it in a separate test environment to work out any issues prior to production deployment. If I hadn't been strongly encouraged (successfully) to de-clutter my software repository, I'd pull out my old Netware 3.12 disks and try installing on a virtual machine. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] P2V of NEtware 3.12 working server to Centos >=5.x
On Thu, 2011-09-08 at 02:35 +0530, Rajagopal Swaminathan wrote: > > I would suggest setting up a CentOS server with Samba and convert the > > DOS network stack, if you can. Samba appears to be much more > > supportable, currently. Take a look at the FreeDOS project, too, as an > > example of getting DOS to work in a more recent environment. The > > biggest concern (after getting the clients to talk to Samba) is that > > there have been a few choices made in Samba with respect to file > > sharing/locking mechanisms. With old software, you may have to look at > > those settings. > > I am not sure about freedos as there is a Piece of custom built ISA > hardware and the forget about replacing it. there is a budget(was > there any?) constraint at clients end. Just suggesting looking at the docs for ideas. > > I google'd netware virtual machine and saw a few > > links to virtualizing Netware 3 under VMWare which might give you some > > insights. > > No additional cash flow for software :p . :) Just another suggested reading for ideas. > > > > Either way, do it in a separate test environment to work out any > > issues prior to production deployment. > > > > Even buying is a hard disk is a constraint. (Cash outflow constraint, > remember :) ) If you can't buy hardware, then you already have a Linux box running KVM? > > If I hadn't been strongly encouraged (successfully) to de-clutter my > > software repository, I'd pull out my old Netware 3.12 disks and try > > installing on a virtual machine. > > > > If only I had that luxury of having those original _working_ floppy disks. > If I had to virtualize an existing machine, I'd boot the equipment with a Linux Live CD and copy (using dd/ssh) the raw disk data to a virtual disk on the virtual machine server. Verify the copy is accurate with md5sum. Then, make another copy to start a virtual machine with. I'd still suggest your best option would be to take one of the DOS clients and get it to connect to a Samba server and migrate the data. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Slightly OT: Centos KVM Host/Guest functions and LVM considerations
On Fri, 2011-09-16 at 10:46 -0700, Eric Shubert wrote: > ... > Now, take all of your ideal logical servers (and the networking which > ties them all together), and make them VMs on your host. I've done this, > and these are the VMs I presently have (the list is still evolving): > .) net (IPCop distro, provides network services, WAN/DMZ/LAN) > .) web (DMZ/STOR) > .) ftp (DMZ/STOR) > .) mail (DMZ/STOR) > .) domain control (LAN/STOR) > .) storage (LAN/STOR) > > One aspect that we haven't touched on is network topology. I have 2 nics > in the host, one for WAN and one for LAN. These are both bridged to the > appropriate subnet. I also have host-only subnets for DMZ and STORage. > The DMZ is used with IPCop port forwarding giving access to services > from the internet. The STOR subnet is sort of a backplane, used by > servers to access the storage VM, which provides access to user data via > SMB, NFS, AFP, and SQL. All user data is accessed via this storage VM, > which has access to raw (non-virtual) storage. > ... If I'm understanding you, if you split this out to multiple physical hosts, you would need to convert DMZ and STOR from virtual to physical segments; increasing the number of required network interfaces in each host to 4. Are you concerned that your hosts are connected to WAN without a firewall? I assume you bridge the interface without assigning IP address? What software do you use for storage. I'd think having the host handle integrated storage would be simpler, but, of course, that doesn't scale to multiple hosts... ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Slightly OT: Centos KVM Host/Guest functions and LVM considerations
I've been considering this type of setup for a distributed virtualization setup. I have several small locations and we would be more comfortable having a host in each. I was nervous about running the firewall as a virtual machine, though if nobody screams bloody murder, I'll start exploring it further as it could reduce machine count at each location by 2 (backup fw). I'm not as paranoid about the host providing storage to the VM's directly, for booting. I'm considering using DRBD to replicate storage on 2 identical hosts to allow fail-over in the case of a host hardware failure. What kind of VM management tool do you use; VMM or something else? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Should I switch and if so what is the procedure
On Wed, 2011-10-05 at 10:55 -0400, Rich wrote: > Since the Xen and Linux kernel people have finally made peace and Xen > is going to be included with the kernel, should I keep using the Xen > virtual server with Centos or should I switch to KVM? I am running > Centos 5.7 now. > I guess the real question is can I still use Xen with Centos 6? The support end of life for CentOS 5 is listed as March 31, 2014 (http://wiki.centos.org/FAQ/General#head-fe8a0be91ee3e7dea812e8694491e1dde5b75e6d). There isn't any pressure, at this point, to convert your VM hosts to CentOS 6 unless there is some feature you require. I doubt RH will add XEN support to RHEL 6. They don't like to add functionality to an existing product. We can hope they bring XEN back in RHEL 7. There was some discussion about producing RPMs to add XEN support into CentOS 6, but I haven't seen any status updates, recently. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Should I switch and if so what is the procedure
On Thu, 2011-10-06 at 01:46 +0200, Dennis Jacobfeuerborn wrote: > ... > The question is what does Xen offer that KVM cannot provide? Looking at the > slides of the KVM Forum 2011 (http://www.linux-kvm.org/page/KVM_Forum_2011) > there seem to be many interesting improvements in the pipeline so at some > point the question really is why hold on to Xen at all when there is not > real reason to? > ... For me, it isn't "why hang onto Xen?", it's "why convert my 18 virtualization servers?" Most of my servers are remote. I have 8 physical locations. Each location has a spare server for redundancy. To change to anything else, I'd need a compelling reason as the time and effort and, potentially, travel expenses would be significant. Looking at scheduled CentOS 5 EOL, I can get other things done before having to tackle major upgrades. When I do start working on my next iteration of my system design, I'll be considering all hypervisors. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Transfer of LVM based guests
On Tue, 2011-11-29 at 15:51 -0500, James B. Byrne wrote: > I am investigating the procedure to follow when moving a > KVM guest instance from one host to another where the > guest uses LVM as its storage. As a preliminary cut I > have cobbled the following together from various sources > located through Google searches: > ... If you are moving the virtual disk, you can't run the virtual machine while you are moving it. Therefore, taking a snapshot (and removing it later) is superfluous. I use md5sum to give myself some extra re-assurance that a copy that big is accurate. Are the virtualization servers at the same location? How often do you move virtual machines? If your virtualization servers are in the same location, you might want to look into setting up a LAN for transferring virtual machine images. It would only take an extra network card in each virtualization server and a Gb Ethernet switch (or better). If you are interested in virtual disk replication, you might want to look at DRBD. It adds an extra layer to your storage, but allows for hot replication of disk space which would allow you to start a virtual machine on any virtualization server. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] server host keys for kvm clones
On Wed, 2012-01-04 at 20:31 +0100, Thomas Göttgens wrote: > Hi James, > > depending on your use case: > > if you source is a template VM: just delete the keys prior to cloning > in the source VM > > if you source is a production VM: just delete the keys after cloning > on the newly cloned VM > > The keys will be regenerated on next startup of openssh if they're > missing. > > am Mittwoch, 4. Januar 2012 um 20:08 schrieben Sie: > > > Respecting cloning vm guests, I see in /etc/ssh the > > following: > > > ssh_host_dsa_key > > ssh_host_dsa_key.pub > > ssh_host_key > > ssh_host_key.pub > > ssh_host_rsa_key > > ssh_host_rsa_key.pub > > > Is there a simple script somewhere to regenerate all the > > server host keys for the new guest after cloning? > Is there a process for pre-generating keys so these keys and .ssh/known_hosts can be pre-filled for all users/hosts? I dislike upgrading servers. I use kickstart from updated sources with integrated configuration files on a new virtual disk to produce an upgraded server without touching the live server. This gives me the chance to test the new server prior to making it live and verifies I can reproduce a failed server at need. Also, this allows me to restage firewalls automatically on a schedule. Let's see a rootkit survive a clean install. Currently, I'm allowing the keys to be regenerated, but it gets annoying editing my known hosts to remove old entries. There's got to be a better way. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] server host keys for kvm clones
On Thu, 2012-01-05 at 15:05 +, Karanbir Singh wrote: > ... > Personally, I hate images. Provisioning from fresh is easy enough, fast > enough and manageable enough that images are almost always either the > wrong solution or a by-product requirement from a third party tool that > does not understand provisioning ( hello, all those so-called-cloud > solutions .. ) > I feel this way too. However, many people espousing imaging are so adamant. I don't argue because it just isn't worth it. Whatever they feel comfortable with as long as I'm not responsible for the result. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] server host keys for kvm clones
On Thu, 2012-01-05 at 15:09 +, Karanbir Singh wrote: > ... Keep in mind that you need to have your provisioning happen in a > fairly secure environment itself, if you are going to add trust points > on signatures like this - specially if they are 'generated' on demand. > Other than installing from a separate network, which is difficult with multiple locations and virtual machines (creating them in a central place then transferring them across the Internet seems unwieldy), what steps can we take to secure the provisioning? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] server host keys for kvm clones
On Thu, 2012-01-05 at 18:15 +0200, Manuel Wolfshant wrote: > ... It depends heavily on the ending result . If you just need a fresh > machine, installing from fresh is ( was for me at least ) the fastest > way. OTOH when you also have a ton of additional applications (maybe not > all of them available as rpm packages) installed / configured... things > might be different. I can accept that custom applications might be easier to include in images. Creating a RPM or install script for a rarely installed program may not make the top of the priority list. However, if it is installed identically on multiple systems, it could be converted to rpm or a scripted install, which could be included in an automated clean install. As an example, I uuencode my current DHCP configuration, DNS files, firewall rules and openvpn certificates into a kickstart file to cleanly install my firewalls. Each is different but is scripted, partly in the scripts that create my kickstart files and partly in the kickstart post section. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] server host keys for kvm clones
On Thu, 2012-01-05 at 21:02 +0200, Manuel Wolfshant wrote: > ... My colleagues from the engineering dept ( I am IT... ) have to use a > commercial application which comes as 2 CD images plus 3 sets of 2 isos > with updates. All of which have to be installed (at last theoretically ) > one after the other and only via their own Java-based installer. > Guess who is not going to rpm-ize the process of installing that 8*450 > MB piece of wonderful software. Nice. The company I work for uses some MS Windows software where the vendor won't even give me install software. They insist the user must call them to install. The user must log into their website to get access to the install software. I don't have a log in, so I don't pre-install that software. The users complain to me and I refer them to the vendor. Yes, some vendors are annoying. It sounds like maybe you'd prefer clean installs but, due to real world compromises, you can't always do that. > And by the way, there are 50% chances that this piece of software was > used in the process of design of your phone. At least if the phone was > engineered after 2000. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Setting up serial ports on kvm guests
On Tue, 2012-01-31 at 14:01 -0500, James B. Byrne wrote: > CentOS-6.2 > > We have a dedicated CentOS-5.7 host used for fax reception > and transmission that we wish to move to a CentOS-6.2 > virtual guest instance. The CentOS-6.2 virtual host has a > 4-port serial card installed. Consider replacing your multi-serial port card with a VoIP analog gateway and use a pre-rolled Asterisk with virtual faxmodems, like Elastix. Just make sure your codec is high enough quality. We used to receive faxes using a dedicated Linux box with a Comtrol Rocketport and an USRobotics MP8. We Converted to SIP trunks and managed to get our faxes in the SIP trunks, as well. This will remove the PCI pass-through from the equation. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Setting up serial ports on kvm guests
On Wed, 2012-02-08 at 13:29 -0500, James B. Byrne wrote: > On Wed, February 8, 2012 11:06, Ed Heron wrote: > > On Tue, 2012-01-31 at 14:01 -0500, James B. Byrne wrote: > >> CentOS-6.2 > >> > >> We have a dedicated CentOS-5.7 host used for fax > >> reception > >> and transmission that we wish to move to a CentOS-6.2 > >> virtual guest instance. The CentOS-6.2 virtual host has > >> a > >> 4-port serial card installed. > > > > Consider replacing your multi-serial port card with a > > VoIP analog > > gateway and use a pre-rolled Asterisk with virtual > > faxmodems, like > > Elastix. Just make sure your codec is high enough > > quality. We used to > > receive faxes using a dedicated Linux box with a Comtrol > > Rocketport and > > an USRobotics MP8. We Converted to SIP trunks and managed > > to get our > > faxes in the SIP trunks, as well. > > > > This will remove the PCI pass-through from the equation. > > > > After a brief read this seems to me the approach we should > take. Recently I have discovered more about irqs, timing > delays, and the difficulties/impossiblities of switching > hardware from vm instances than I ever wanted to know. > > Given that we have three dedicated fax lines and 6 voice > is there any hardware that would you suggest for a 4 core > x86_64 Intel based host system? > > We have looked at going completely to v/f-oip but I do not > have the time to deal with those intricacies and get this > move completed at the same time. So, for the nonce it > appears that we would have to employ an FXO gateway to > connect our existing POTS lines to the host. It might be OK to virtualize a fax server, but I wouldn't switch to a new voice tech and virtualize it at the same time. If you are interested in moving to a VoIP phone system, you should get familiar with how it works before adding the virtual component. Currently, I'm running a couple of locations using Elastix with dedicated hardware. One location supports 6 users with an Intel D845G integrated desktop board with a 1.7 Celeron and 1G RAM, so the hardware requirements are pretty low, but virtualized machines are not necessarily real-time. I would consider virtualizing it if I dedicated a server CPU and network card, but you'd need to find an external analog VoIP gateway that you are comfortable with. I'm currently using internal Digium cards for T1 and analog connectivity, but obviously I'd want to move to an external gateway or move to pure SIP before virtualizing to avoid having a PCI passthrough issue of my own. Just make sure that your phone line vendor is not using VoIP internally and handing you an emulated analog interface. I had quite a mess when I tried connecting an analog/VoIP external gateway to some emulated analog lines. The 2 analog emulations didn't quite mesh and I had miscellaneous dropped calls. The issue hurt my department's credibility and led to a longer implementation schedule for our VoIP project. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Resize guest filesystem question
On Fri, 2012-02-24 at 12:05 -0800, Jeff Boyce wrote: > Greetings - > > I am going through some testing steps to expand a logical volume and the > corresponding filesystem on a KVM guest and have run across a deficiency in > my knowledge. I spent the afternoon yesterday googling for answers, but had > have come up blank still. What I am trying to do is resize the file system > to use the additional disk space that I added to the logical volume that the > guest uses. Here is what I have done and the details of my system. > > 0. Both my host and guest are running Centos 6.2. > > 1. My KVM host system has the LVM volume group that is divided into logical > volumes which are then presented to the KVM guests as raw space. > > 2. A guest may use 2 or 3 logical volumes from the host system for its > filesystem (/, /var, /data) and I have logical volumes named within the host > system by guest and mount point so that I know what each logical volume is > assigned to by it's name. > > 3. I expanded a specific logical volume on the host (/dev/vg/lv_guest1root) > that is used by Guest1, and I can see in vgdisplay and lvdisplay that the > logical volume was properly expanded. > > 4. I then issued a resize2fs /dev/vg/lv_guest1root command (on the host) > to resize the filesystem to the expanded logical volume. This resulted in a > message that it essentially couldn't find a valid filesystem superblock. > Well of course then I realized that there is no filesystem on the logical > volume from the perspective of the host. The filesystem wasn't set on the > logical volume until the guest installation occurred. > > 5. So then I switched over to the guest system and ran df -h to see the > existing filesystem > > [root@guest1 jeffb]# df -h > FilesystemSize Used Avail Use% Mounted on > /dev/vda2 4.5G 2.3G 2.0G 53% / > tmpfs1004M 88K 1004M 1% /dev/shm > /dev/vda1 485M 30M 430M 7% /boot > /dev/vdb1 2.0G 219M 1.7G 12% /var > > 6. Then I ran resize2fs /dev/vda2 and got the result that the filesystem > is already xx blocks long. Nothing to do! > > So here is where I am stuck. Guest1 is my test system so it only has the / > and /var logical volumes, whereas the production guest (guest2) that I will > be expanding also has /data, which will be the logical volume that I will > expand. So two things I did not do where, I did not shut down the guest VM, > and I did not unmount the filesystem before asking it to resize. However my > research before doing this did not seem to indicate that I had to do either, > and the message about nothing to do also seems to indicate that they were > not necessary. > > So I am missing a hole in my knowledge and additional googling has not > helped to fill it. I must be missing something simple. Is this result due > to the fact that I am testing on expanding the / filesystem, and it would > work properly on a guest system that had /data? Do I need to unmount the > filesystem, or shut down the guest VM, or mount the guest from a LiveCD? Or > do I need to give it resize2fs /dev/vda rather than specifically > /dev/vda2 ? Any clues, or pointers to good documentation is greatly > appreciated. Thanks. The guest put a partition table on the LV. To resize the filesystem, the partition must be resized, as well. There are several ways to do it. I think some people use gparted. To recap the steps, resize the LV, resize the partition, resize the filesystem. I setup a separate guest with the required tools to resize my guest filesystems and temporarily take down the guest to give the disk space to the utility guest. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] routing problem with domU bridged to two networks
On Wed, 2012-03-07 at 20:41 +0200, Peter Peltonen wrote: > As I received no response on the general CentOS list, I'll repost it > here as the question is about Xen virtual machine routing. > > > This is my network setup: > http://pastebin.com/kyWpTQYU > > > Lets assume my dom0's eth2 public ip is 1.2.3.33 and my dmz network > 11.22.33.96/255.255.255.224 . I have created NAT from my LAN with > iptables. You can see my /etc/sysconfig/iptables here: > http://pastebin.com/1FqSTvPH > > > And this is my dom0 routing table: > http://pastebin.com/gNjTFHp5 > > > My goal: > > To access NFS shares on a (non-virtualized) file server in the LAN > network from the domU web server in the DMZ network. > > > What I tried: > > I attached the domU to both bridges using this Xen config: > > vif = [ > "mac=00:0c:29:de:3a:fe,bridge=xenbr0","mac=00:0C:29:76:19:85,bridge=xenbr1" > ] > > and then created two eth interfaces inside the domU mapping to the MAC > addresses above, giving eth1 an IP from the DMZ (11.22.33.111) and > giving eth2 an IP from the LAN (192.168.0.12). After this I mounted > the NFS share from the file server (192.168.0.2). > > > My problem: > > If my domU web server is connected to both LAN and DMZ using the two > bridges xenbr0 and xenbr1, I can access the NFS share from the domU > web server and everything else works as expected, except for one thing > -- my workstations in the LAN cannot anymore access the web server: > web pages do not open anymore and from the workstations I cannot ping > the domU. If the web server domU is only connected to DMZ via xenbr0, > the workstations can access it ok. > > > Any advice what I am doing wrong and I could fix my setup? The postrouting command uses -o eth2. To NAT LAN requests to your DMZ web server, shouldn't you be using xenbr0? Though, I would bridge eth2, as well, and create a virtual firewall with eth0 (DMZ?), eth1 (LAN) and eth2 (PUB). I wouldn't want the Dom0 to be directly compromised if my firewall was compromised. > Regards, > Peter > ___ > CentOS-virt mailing list > CentOS-virt@centos.org > http://lists.centos.org/mailman/listinfo/centos-virt ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] routing problem with domU bridged to two networks
On Wed, 2012-03-07 at 13:13 -0700, Ed Heron wrote: > On Wed, 2012-03-07 at 20:41 +0200, Peter Peltonen wrote: > > As I received no response on the general CentOS list, I'll repost it > > here as the question is about Xen virtual machine routing. > > > > > > This is my network setup: > > http://pastebin.com/kyWpTQYU > > > > > > Lets assume my dom0's eth2 public ip is 1.2.3.33 and my dmz network > > 11.22.33.96/255.255.255.224 . I have created NAT from my LAN with > > iptables. You can see my /etc/sysconfig/iptables here: > > http://pastebin.com/1FqSTvPH > > > > > > And this is my dom0 routing table: > > http://pastebin.com/gNjTFHp5 > > > > > > My goal: > > > > To access NFS shares on a (non-virtualized) file server in the LAN > > network from the domU web server in the DMZ network. > > > > > > What I tried: > > > > I attached the domU to both bridges using this Xen config: > > > > vif = [ > > "mac=00:0c:29:de:3a:fe,bridge=xenbr0","mac=00:0C:29:76:19:85,bridge=xenbr1" > > ] > > > > and then created two eth interfaces inside the domU mapping to the MAC > > addresses above, giving eth1 an IP from the DMZ (11.22.33.111) and > > giving eth2 an IP from the LAN (192.168.0.12). After this I mounted > > the NFS share from the file server (192.168.0.2). > > > > > > My problem: > > > > If my domU web server is connected to both LAN and DMZ using the two > > bridges xenbr0 and xenbr1, I can access the NFS share from the domU > > web server and everything else works as expected, except for one thing > > -- my workstations in the LAN cannot anymore access the web server: > > web pages do not open anymore and from the workstations I cannot ping > > the domU. If the web server domU is only connected to DMZ via xenbr0, > > the workstations can access it ok. > > > > > > Any advice what I am doing wrong and I could fix my setup? > > The postrouting command uses -o eth2. To NAT LAN requests to your DMZ > web server, shouldn't you be using xenbr0? > > Though, I would bridge eth2, as well, and create a virtual firewall > with eth0 (DMZ?), eth1 (LAN) and eth2 (PUB). I wouldn't want the Dom0 > to be directly compromised if my firewall was compromised. I'd also add a fourth network interface for SAN, then you can connect 2 virtual servers together and use DRBD to replicate your disk space for fault tolerance. Your firewall could be started on either machine. > > Regards, > > Peter > > ___ > > CentOS-virt mailing list > > CentOS-virt@centos.org > > http://lists.centos.org/mailman/listinfo/centos-virt > ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Basic shared storage + KVM
On Tue, 2012-06-19 at 18:21 +0200, Andrea Chierici wrote: > Hi, > I am trying to set up a shared iscsi storage to serve 6 kvm hypervisors > running centos 6.2. > I export an LVM from iscsi and configured virt-manager to see the iscsi > space as LVM storage (a single storage pool). > I can create space on this LVM storage pool directly from virt-manager > and I am already running a couple of sample VMs, that do migrate from > one hv to the other. > > This configuration has a problem: when I create a new LV on the LVM > storage pool to host a new VM, the HV where I am creating the virtual > machine on sees the LV as status "available", while the others see it as > "NOT available". In some circumstances this can crash libvirtd. To fix > this I generally issue: > > vgchange -an; sleep 1; vgchange -ay > > but sometimes this fails with error: > > device-mapper; create ioctl failed: Device or resource busy > > and anyway it's not very convenient to issue this command on every node > every time a new LV is created. > Can anyone suggest a solution (if any) to this problem? > Keep in mind that the basic concept behind this approach is to keep > things as simple as possible. I don't want to configure a cluster or any > other complicated tool to simply be able to migrate VMs from one HV to > another. > Thanks, > > Andrea Please help me understand why you are doing it this way? I'm using Xen with integrated storage, but I've been considering separating my storage from my virtual hosts. Conceptually, we can ignore the Xen/KVM difference for this discussion. I would imagine using LVM on the storage server then setting the LVs up as iSCSI targets. On the virtual host, I imagine I would just configure the new device and hand it to my VM. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] How do boot a xen domu into run level 1
You could loop mount the messed up disk on the host or you could mount the messed up disk on another DomU and change it. On Thu, 2012-09-20 at 08:58 -0400, m...@tdiehl.org wrote: > Hi, > > I have a C5.8 machine with several DomU's. I fubared the fstab on one of them > and I need to get it into single user mode. > > Does anyone know how to do that? I tried adding single to the extras line > in /etc/xen/machine_name but it still tries to start in level 3. > > To make things worse, the root partition is on LVM. > > Alternatively, does anyone know how to access the image from DomU? I tried > to use kpartx but when I run VGscan, I do not get the lvm activated. > > Regards, > ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] How do boot a xen domu into run level 1
On Thu, 2012-09-20 at 12:03 -0400, m...@tdiehl.org wrote: > On Thu, 20 Sep 2012, Ed Heron wrote: > > > You could loop mount the messed up disk on the host or you could mount > > the messed up disk on another DomU and change it. > > Yes, I thought about mounting it on another DomU right after I sent the > message to the list and that worked. It even activated the lvm partitions. > > I am still wondering why I cannot get the thing into Run level 1 though. > > I see numerous people on the net talking about just adding single to the > extras line in the xen config file but that does not work. > > Thanks for the help. > > Regards, > You could set the default runlevel in /etc/inittab when the disk is mounted on another VM... ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] How do I boot a xen domu into run level 1
On Fri, 2012-09-21 at 12:05 -0400, m...@tdiehl.org wrote: > ... > If I use virt-manager to make changes to the configuration, I see the > changes in /etc/xen/vm_name > > I am now wondering if there is another config file some where that > virt-manager > is writing to. > ... You could also run "virsh edit " ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Package lists for Cloud images
On Wed, 2012-10-03 at 17:29 +0100, Karanbir Singh wrote: > hi Guys, > > As we get ready to start publishing Cloud Images ( or rather images > consumable in various virt platforms, including public and private > clouds ) - it would be great to have a baseline package manifest worked > out. > > What / how many images should we build. At this time we were thinking of > doing : > > - CentOS-5 32bit minimal > - CentOS-6 32bit minimal > > - CentOS-5 64bit minimal > - CentOS-6 64bit minimal > > - CentOS-5 64bit LAMP > - CentOS-6 64bit LAMP > > What would be the minimal functional requirements people would expect > from these images ? and what rpms should be installed ? Should root > login be enabled or should we require people to go in via a 'centos' > user. Should the image be self-updating, or should we have a post-login > message that indicates outstanding updates ? Are you using existing RPMs or creating new ones with stripped dependencies? What advantages will these images have over a kickstart install from a local repo? ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Preferred method of provisioning VM images
On Tue, 2014-06-10 at 17:21 +0100, Lars Kurth wrote: > Hi all, > > following the discussion on about documentation, I was wondering whether > we need to look at a standard way in which we recommend how to provision > images for VMs. Am starting this with a Xen hat, but the discussion > should not be specific to this. There are a number of options, but all > have some trade-offs > > == #1 virt-install == > > Advantages: similar to KVM > > Disadvantages: may cause weird issues / confusion with people switching > back to xl. The core issue is that with the current version of xen and > libvirt, this only works with xm (when xl is used, this can create some > undefined behavior). However as we have seen in some recent threads on > this list, people tend to mix which can cause problems. > ... I've chosen the virt-install method on CentOS 5 precisely because it is like KVM. I was hoping it would fulfill the promise of being hypervisor agnostic. I'm hoping it continues to be available on future versions of CentOS with Xen. Though it is a waste of resources, I make all my virtual machines, Linux and MS Windows alike, fully virtualized. I can then move any of the VM's with the same virt-install --import or virsh dumpxml/edit/virsh define process. When moving a VM, usually the only thing I have to do outside of virt-install/virt-manager is add , or , which can be done with virsh edit. I don't know why some of my virtual servers need them and other don't but I have higher priority things to think about. I'm the only technical support person and I don't work 24/7. The graphical interface of virt-manager makes it possible for non-tech people to see what is running and see consoles to restart any misbehaving VM's (usually MS Windows VM's). I have completely eliminated my use of xm. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] Preferred method of provisioning VM images
If networking is already configured when a VM boots, how about a kernel parameter for a configuration server? If it is configured to grab an executable file, it would be very flexible. We use kickstart files to build our CentOS VM's and physical boxes and then pull configuration changes from a server at regular intervals. I'm working on extending our existing internal intranetto keep history and to allow a single change to propagate to all relevant servers. Also would allow fail2ban to share it's banned IP's. Since this is specific to our internal systems, it can't easily be exported, but most of it is pretty straight forward. It could almost be integrated into an existing CMS. Think WebMin but in a LISA (Large Installation System Administration) environment. A similar technique could be used for cloud machines. ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
[CentOS-virt] LVM mirror database to ramdisk
I'm still running CentOS 5 with Xen. We recently replaced a virtual host system board with an Intel S1400FP4, so the host went from a 4 core Xeon with 32G RAM to a 6 core Xeon with 48G RAM, max 96G. The drives are SSD. I was recently asked to move an InterBase server from Windows 7 to Windows Server. The database is 30G. I'm speculating that if I put the database on a 35G virtual disk and mirror it to a 35G RAM disk, the speed of database access might improve. I use local LVM for my virtual disks with DRBD on top to mirror the disk to a backup server. If I change grub.conf to increase RAM disk size and increase host RAM, I could create a 35G RAM disk. I'd modify rc.local to add pvcreate /dev/ramdisk vgextend vg /dev/ramdisk lvconvert -m 1 --corelog vg/lv_database /dev/ramdisk Even with lv_database being 35G, it doesn't take long to activate the mirror. I haven't decided where to put the commands to turn off the lvm mirror. lvconvert -m 0 vg/lv_database vgreduce vg /dev/ramdisk pvremove /dev/ramdisk I haven't put this in real world use, yet. On it's face, this might speed up database access. Would we expect it to speed up database access in real world use? Should I document the process so others could know how to do this? I realize new documentation for CentOS 5 virtualization would be considered obsolete before I wrote it but I'm expecting to test CentOS 7 virtualization in the next few months and, when I am comfortable, I'd upgrade my 18 virtual hosts. I would update the documentation, at that time, as well. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] LVM mirror database to ramdisk
On Fri, 2016-01-22 at 14:56 -0600, NightLightHosts Admin wrote: > On Fri, Jan 22, 2016 at 11:02 AM, Ed Heron wrote: > > I'm still running CentOS 5 with Xen. > > > > We recently replaced a virtual host system board with an Intel > > S1400FP4, so the host went from a 4 core Xeon with 32G RAM to a 6 core > > Xeon with 48G RAM, max 96G. The drives are SSD. > > > > I was recently asked to move an InterBase server from Windows 7 to > > Windows Server. The database is 30G. > > > > I'm speculating that if I put the database on a 35G virtual disk and > > mirror it to a 35G RAM disk, the speed of database access might improve. > > > > I use local LVM for my virtual disks with DRBD on top to mirror the > > disk to a backup server. > > > > If I change grub.conf to increase RAM disk size and increase host RAM, > > I could create a 35G RAM disk. > > > > I'd modify rc.local to add > > pvcreate /dev/ramdisk > > vgextend vg /dev/ramdisk > > lvconvert -m 1 --corelog vg/lv_database /dev/ramdisk > > > > Even with lv_database being 35G, it doesn't take long to activate the > > mirror. > > > > I haven't decided where to put the commands to turn off the lvm > > mirror. > > lvconvert -m 0 vg/lv_database > > vgreduce vg /dev/ramdisk > > pvremove /dev/ramdisk > > > > I haven't put this in real world use, yet. > > > > On it's face, this might speed up database access. Would we expect it > > to speed up database access in real world use? > > > > Should I document the process so others could know how to do this? I > > realize new documentation for CentOS 5 virtualization would be > > considered obsolete before I wrote it but I'm expecting to test CentOS 7 > > virtualization in the next few months and, when I am comfortable, I'd > > upgrade my 18 virtual hosts. I would update the documentation, at that > > time, as well. > > > I may not understand enough to understand what you are doing, you want > to actively mirror this with LVM or? Yes, in a test environment, I am mirroring a Logical Volume with a RAM disk to increase the perceived speed of the disk. I'm expecting to convert a live guest to this type of setup, this weekend. I was asking 2 questions. 1. Should I expect a significant increase in speed in a real world environment? With enough RAM, a good caching system will eventually do a similar function. This is almost like pre-loading a cache. 2. Should I document the process for others? I'm using CentOS 5 now, which is on it's way out, but I would update the documentation to include CentOS 7 when I upgrade my servers. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] LVM mirror database to ramdisk
On Fri, 2016-01-22 at 16:17 -0600, NightLightHosts Admin wrote: > > Ed Heron wrote: > > Yes, in a test environment, I am mirroring a Logical Volume with a RAM > > disk to increase the perceived speed of the disk. I'm expecting to > > convert a live guest to this type of setup, this weekend. > > > > I was asking 2 questions. > > 1. Should I expect a significant increase in speed in a real world > > environment? With enough RAM, a good caching system will eventually do > > a similar function. This is almost like pre-loading a cache. > > 2. Should I document the process for others? I'm using CentOS 5 > > now, > > which is on it's way out, but I would update the documentation to > > include CentOS 7 when I upgrade my servers. > > > > See this is where I was confused. Would not the LVM mirror have to > sync all the time with the disk anyways? Yes, but it isn't that simple. One copy of the mirror would be on a physical disk. The other copy of the mirror would be on RAM disk. Since data in RAM doesn't generally survive reboot, the RAM piece would need to be turned off before shutdown and created on startup. > Is there something about LVM mirroring that can handle disks of > different speeds? With newer LVM, there appears to be some settings that might help with that a bit. With this older verion, I'd be hoping that the next available disk would handle each request. If the physical disk takes longer to deal with the writes, the RAM disk might be the one that is available most of the time. I'd much prefer a method of pre-filling a 35G cache but I saw a reference to creating a disk mirror in RAM and decided to explore it. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] LVM mirror database to ramdisk
On Fri, 2016-01-22 at 16:59 -0600, NightLightHosts Admin wrote: > On Fri, Jan 22, 2016 at 4:54 PM, Ed Heron wrote: > > Yes, but it isn't that simple. One copy of the mirror would be on a > > physical disk. The other copy of the mirror would be on RAM disk. > > Since data in RAM doesn't generally survive reboot, the RAM piece would > > need to be turned off before shutdown and created on startup. > > > >> Is there something about LVM mirroring that can handle disks of > >> different speeds? > > > > With newer LVM, there appears to be some settings that might help with > > that a bit. With this older verion, I'd be hoping that the next > > available disk would handle each request. If the physical disk takes > > longer to deal with the writes, the RAM disk might be the one that is > > available most of the time. > > > > I'd much prefer a method of pre-filling a 35G cache but I saw a > > reference to creating a disk mirror in RAM and decided to explore it. > > > > Can you post the results of your test when you get it working? Absolutely, I'll share my real world results. I'm happy that I'm not the only person interested in the technique. I'm a little disappointed somebody isn't telling me there is a much simpler method of putting my database in RAM. The technique is only useful in a situation where the server has gobs of RAM so it might only apply to a small subset of users but it might speed up database access. And since it is being done by the virtual host, the guest doesn't need to know anything about it. This keeps guest complexity down. Also, I don't have as much Windows knowledge as I have Linux knowledge so it was easier for me to implement under Linux. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] LVM mirror database to ramdisk
On Fri, 2016-01-22 at 17:39 -0600, NightLightHosts Admin wrote: > Ed Heron wrote: > > Absolutely, I'll share my real world results. I'm happy that I'm not > > the only person interested in the technique. I'm a little disappointed > > somebody isn't telling me there is a much simpler method of putting my > > database in RAM. The technique is only useful in a situation where the > > server has gobs of RAM so it might only apply to a small subset of users > > but it might speed up database access. And since it is being done by > > the virtual host, the guest doesn't need to know anything about it. > > This keeps guest complexity down. Also, I don't have as much Windows > > knowledge as I have Linux knowledge so it was easier for me to implement > > under Linux. > > > See, > > This is where I get confused again, which type of database is it? It is a Customer Relationship Management database running under InterBase on Microsoft Windows Server. However, because the database server is a virtual machine, it doesn't matter. The technique could be useful for speeding up any disk-centric activity. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] LVM mirror database to ramdisk
On Sat, 2016-01-23 at 09:27 -0600, Robert Nichols wrote: > On 01/22/2016 11:02 AM, Ed Heron wrote: > >I'm still running CentOS 5 with Xen. > > > >We recently replaced a virtual host system board with an Intel > > S1400FP4, so the host went from a 4 core Xeon with 32G RAM to a 6 core > > Xeon with 48G RAM, max 96G. The drives are SSD. > > > >I was recently asked to move an InterBase server from Windows 7 to > > Windows Server. The database is 30G. > > > >I'm speculating that if I put the database on a 35G virtual disk and > > mirror it to a 35G RAM disk, the speed of database access might improve. > > If that were running under Linux rather than Windows I'd suggest just > giving that extra 35GB to its kernel and letting its normal caching > keep everything in RAM. Whether Windows (7 or Server) would be clever > enough to do that is another question. Of course you could just let > the Linux host do the caching, but that runs the risk of other VMs > or host activity displacing some of that cache and affecting the > performance of your database VM. > Yes... You've got much of my thought process. The RAM disk mirror pre-loads the database into memory and forces it to stay in RAM. ___ CentOS-virt mailing list CentOS-virt@centos.org https://lists.centos.org/mailman/listinfo/centos-virt
