Re: [CentOS] Cluster SW

[Rajagopal Swaminathan]

Greetings,


On Thu, Apr 11, 2013 at 2:30 PM, santosh venkataswamy wrote:

>
>
>  Hi,
>  How to download  Cluster SW and how to configure clustering in CentOS.
> With Regards and  good wishes.
>
> V.SANTOSH
>

What type of cluster are you referring to: HA or HPC?

Accordingly the answer will depend.

Please note in HA domain, there are no lock-step clusters yet in Linux,
AFAIK.

-- 
Regards,

Rajagopal
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Re: [CentOS] How to determine why a server is not responding

[nan del bosc]

Alexander Dalloz, true, but I'm only a system administrator guy who do the
work that tells the boss... ;)

Kai Schaetzl, yes! you are right, I should have said this in the beginning!
Sorry, it's because of the hurry... ;)

Thank's for all your answer! I wrote a mail to my provider. I keep you
informed!


2013/4/11 Dale Dellutri 

> On Thu, Apr 11, 2013 at 10:59 AM, nan del bosc 
> wrote:
>
> > ...
> > This is a Virtual Server from 1and1, I cannot access the BIOS...
> >
> > any other idea?
> >
>
> If this is a virtual server, the actual hardware may just be running
> other virtual servers and you're not getting any resources.  If that's
> true, nothing you do from your server will help you.  You'll need to
> get system stats from the actual hardware provider.
>
> Sounds like the hardware is over-committed.  Do you have some
> kind of service guarantee?
>
> --
> Dale Dellutri
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---
Salut!
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Re: [CentOS] [OT] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 10:48 PM, Keith Keller wrote:
> (As an aside, how
> does the kernel handle more than 26 hard drive devices?  sdaa?  sdA?)

sdaa, sdab, sdac, ... sdba, sdbb, sdbc  etc etc.

and yes, if you have 40+ disks as JBOD, its a bloody mess, especially if 
linux udev starts getting creative.

many of the systems I design get deployed in remote DCs and are 
installed, managed and operated by local personnel where I have no clue 
as to the levels of their skills, so its in my best interest to make the 
procedures as simple and failsafe as possible.   when faced with a wall 
of 20 storage servers, each with 48 disks, good luck with finding that 
20 digit alphanumeric serial number "3KT190V2754280ED"   ... uh HUH, 
thats assuming all 960 disks got just the right sticker put on the 
caddies.'replace the drives with the red blinking lights' is much 
simpler than 'figure out what /dev/sdac is on server 12'

-- 
john r pierce  37N 122W
somewhere on the middle of the left coast

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Re: [CentOS] [OT] RAID 6 - opinions

[Keith Keller]

On 2013-04-12, David Miller  wrote:
>
> On Apr 11, 2013, at 5:25 PM, John R Pierce  wrote:
>
>> yeah, until a disk fails on a 40 disk array and the chassis LEDs on the 
>> backplane don't light up to indicate which disk it is and your 
>> operations monkey pulls the wrong one and crash the whole raid.

[snip]

> You simply match up the Linux /dev/sdX designation with the drives serial 
> number using smartctl. When I first bring the array online I have a script 
> that greps out the drives serial numbers from smartctl and creates a neat 
> text file with the mappings. When either smartd or md complain about a drive 
> I remove the drive from the RAID using mdadm and then pull the drive based on 
> the mapping file. Drive 0 in those SuperMicro SAS/SATA arrays are always the 
> lowest drive letter and goes up from there. If a drive is replaced I just 
> update the text file accordingly. You can also print out the drive serial 
> numbers and put them on the front of the removable drive cages. It is not as 
> elegant as a blinking LED but it works just as well.  I have been doing it 
> like this for 6 plus years now with a few dozen SuperMicro arrays. I have 
> never pulled a wrong drive.  

I think that there is at least one potential problem, and possibly more,
with your method.

1) It only takes once forgetting to update the mapping file to screw
things up for yourself.  Some people are the type who will never forget
to do that.  I'm (unfortunately) not.  (Actually, I guess it takes
twice, since if you have only one slot not up to date, you could use the
serial numbers to map all but the one drive, and that's the suspect
drive.  I wouldn't want to trust that process.)

2) Drive assignments can be dynamic.  If you pull the tray in port 0,
which was sda (for example), you're not necessarily guaranteed that the
replacement drive will be sda.  It might be assigned the next available
sdX.  I have seen this in certain failure situations.  (As an aside, how
does the kernel handle more than 26 hard drive devices?  sdaa?  sdA?)

1a and 2a) Printing serial numbers and taping them to the tray is much
less error-prone, but also more time consuming.  If you have a label
printer that certainly makes things easier.

3) If you have someone else pulling drives for you, they may not have
access to the mapping file, and/or may not be willing or under contract
to print a new tray label and replace it.  It's way less error-prone to
tell an "operations monkey" to pull the blinky drive than to hope you
read the mapping file correctly, and relay the correct location to the
monkey.  (The ops monkey may not have login rights on your server, so
you also can't rely on him being able to look at the mapping file
himself.)  If you're the only person who will ever pull drives, this
isn't such a huge problem.

That's not to say that your methods can't work--obviously they can if
you haven't had any mistakes in many years.  But the combination of a
BBU-backed write cache and an identify blink makes a dedicated hardware
RAID controller a big win for me.  (I do also use md RAID, even on
hardware RAID controllers, where flexibility and portability are more
important than performance.)

--keith

-- 
kkel...@wombat.san-francisco.ca.us


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Re: [CentOS] RAID 6 - opinions

[Adrian Sevcenco]

On 04/11/2013 06:36 PM, m.r...@5-cent.us wrote:
> I'm setting up this huge RAID 6 box. I've always thought of hot spares,
> but I'm reading things that are comparing RAID 5 with a hot spare to RAID
> 6, implying that the latter doesn't need one. I *certainly* have enough
> drives to spare in this RAID box: 42 of 'em, so two questions: should I
we use several of this kind of boxes (but with 45 trays) and our
experience was that the optimum volume size was 12 hdds (3 X 12 + 9)
which will reduce the 45 disks to a actual size of 37 disks (a 12 disk
volume is 40 TB size ... in event of a broken hdd it takes 1 day to
recover.. more than 12 disks and i dont (want to) know how long it would
take) and we don't use hot spares.

HTH,
Adrian

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Re: [CentOS] RAID 6 - opinions

[David Miller]

On Apr 11, 2013, at 5:25 PM, John R Pierce  wrote:

> On 4/11/2013 5:04 PM, David C. Miller wrote:
>> The LSI 9200's I use are nothing more than a dumb $300 host bus adapter. No 
>> RAID levels or special features. I prefer to NOT use hardware RAID 
>> controllers when I can. With a generic HBA the hard drives are seen raw to 
>> the OS. You can use smartctl to poll and test the drives just like they were 
>> connected to a generic SATA bus on the motherboard. The tools built into 
>> Linux(smartd & md) are better suited and more flexible at reporting problems 
>> and handling every level of RAID. It also makes migrating the array to 
>> another system trivial. I don't have to worry about finding the exact same 
>> RAID controller. Just a no frills SAS/SATA HBA will do.
> 
> yeah, until a disk fails on a 40 disk array and the chassis LEDs on the 
> backplane don't light up to indicate which disk it is and your 
> operations monkey pulls the wrong one and crash the whole raid.
> 
> have fun with that!
> 
> if you can figure out how to get the drive backplane status LEDs to work 
> on Linux with a 'dumb' controller plugged into a drive backplane, PLEASE 
> WRITE IT UP ON A WIKI SOMEWHERE!!!   everything I've seen leaves this 
> gnarly task as an exercise to the reader. With a card like a 9261-8i, it 
> just works automatically.
> 
> also, hardware raid controllers WITH battery backed (or flash backed) 
> cache can greatly speed up small block write operations like directory 
> entry creates, database writes, etc.
> 

You simply match up the Linux /dev/sdX designation with the drives serial 
number using smartctl. When I first bring the array online I have a script that 
greps out the drives serial numbers from smartctl and creates a neat text file 
with the mappings. When either smartd or md complain about a drive I remove the 
drive from the RAID using mdadm and then pull the drive based on the mapping 
file. Drive 0 in those SuperMicro SAS/SATA arrays are always the lowest drive 
letter and goes up from there. If a drive is replaced I just update the text 
file accordingly. You can also print out the drive serial numbers and put them 
on the front of the removable drive cages. It is not as elegant as a blinking 
LED but it works just as well.  I have been doing it like this for 6 plus years 
now with a few dozen SuperMicro arrays. I have never pulled a wrong drive.  

David.
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Re: [CentOS] centos 6.3 ipv6 default gateway

[Jaze Lee]

2013/4/12 Michael H. Warfield 

> On Fri, 2013-04-12 at 09:28 +0800, Jaze Lee wrote:
> > 2013/4/12 Michael H. Warfield 
> >
> > > Hello,
> > >
> > > I may be totally off base here but...
> > >
> > > On Thu, 2013-04-11 at 18:06 +0800, Jaze Lee wrote:
> > > > hello,
> > > >i met a problem in configuratiion of ipv6 gw in my box
> > > > i install centos 6.3 (64 bit) on my boxs, which have four netcard.
> > > > i use a straight-through cable to connect centosv0:netcard-2 and
> > > > centosv1:netcard2
> > > > the topology is this:
> > > > client c(windows xp) <-->centosv0:netcard-3 <--> centosv0:netcard-2
> <--->
> > > > centosv1:netcard-2 <>centosv1:netcard-2  <---> client d
> (backtrack r2
> > > > 32)
> > > > 1:2:3:4::2/64  1:2:3:4::1/64
> 1:2:3::4/64
> > > >   1:2:3::5/64 1:2:3:5::1/64
> > > >  1:2:3:5::2/64
> > >
> > > Surely, I hope you jest with those numbers.  You are not allowed to
> pick
> > > numbers out of the air and just use them, even if it's for private use.
> > > There are specific blocks of addresses for specific uses and assigned
> > > "scopes" and all the "private use" addresses are in blocks very high up
> > > in the address space beginning with fc or fd.  If those are literally
> > > the addresses you used, they will not work and I would expect them to
> > > give you all sorts of grief at some point or another.
> > >
> > > > what i want to do is set default gw on centosv0 to centosv1
> > >
> > > I take it "centosv0"  and "centosv1" are configured for ipv6
> forwarding?
> > > You didn't provide the information on that.  There are some gotcha's in
> > > there with default routing on a router (basically there is no such
> > > thing) and the router needs to be set up properly for both routing and
> > > its routes.  But I don't think that's your problem you're describing
> > > down below.
> > >
> > > > i configure /etc/sysconfig/network-scripts/ifconfig-eth2  (centosv0)
> as
> > > this
> > > > DEVICE="eth2"
> > > > BOOTPROTO=static
> > > > HWADDR="60:A4:4C:23:2F:6F"
> > > > NM_CONTROLLED="yes"
> > > > ONBOOT="yes"
> > > > TYPE="Ethernet"
> > > > #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> > > > IPV6INIT=yes
> > > > IPV6ADDR=1:2:3::4
> > >  ^^ You didn't specify a netmask here (default /128).
> > >
> > > > IPV6_DEFAULTGW=1:2:3::5
> > >   Technically not on your interface's network
> > > (/128)
> > >
> > > > and i also configure /etc/sysconfig/network to this:
> > > > NETWORKING=yes
> > > > HOSTNAME=centosv0
> > > > NETWORKING_IPV6=yes
> > > > IPV6_AUTOCONF=no
> > >
> > > For forwarding...
> > >
> > > In that file you're also going to need:
> > >
> > > IPV6FORWARDING=yes
> > >
> > > You may also need to add lines to /etc/sysctl.conf (I've needed in the
> > > past on Fedora):
> > >
> > > net.ipv6.conf.all.forwarding = 1
> > > net.ipv6.conf.default.forwarding = 1
> > >
> > > But those aren't your problem with this...
> > >
> > > > but i met an error:
> > > > Bringing up interface eth2:  WARN : [ipv6_add_route] Unknown
> error
> > >
> > > I'm not totally sure if this is because you didn't specify a prefix
> > > length on your IPV6ADDR line or the fact that it then conflicted with
> > > your IPV6_DEFAULTGW which would not have been on 1:2:3::4/128 or if it
> > > was because you choose and illegal IPv6 prefix or if it was a
> > > combination of all of them.  The "WARN: [ipv6_add_route] Unknown error"
> > > makes me suspicious because your default gatway conflicts with your
> > > interface network definition (because you didn't specify the prefix
> size
> > > and it defaulted to /128) and the kernel has no way to route it out any
> > > interface.  IAC...  You won't be able to use a default route on a
> router
> > > anyways (more below).
> > >
> > > > i do not know how why,and can some one gives me some suggestion?
> > > > thanks a lot.
> > >
> > > If those were literally the addresses you used, It may be an address
> > > that's in an illegal scope.
> >
> >   i test those ipv6 address on ubuntu 12.04, and it is ok. But now, we
> > should change system to Centos 6.3.
> >   And i add all the stuff that i miss. One machine is configured like
> this:
> >
> >  [root@centosv0 sysconfig]# cat
> /etc/sysconfig/network-scripts/ifcfg-eth2
> > DEVICE="eth2"
> > BOOTPROTO=static
> > HWADDR="60:A4:4C:23:2F:6F"
> > NM_CONTROLLED="yes"
> > ONBOOT="yes"
> > TYPE="Ethernet"
> > #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> > IPV6INIT=yes
> > IPV6ADDR=1:2:3::4/64
> > IPV6_DEFAULTGW=1:2:3::5/64
>  ^^^  You do NOT need the /64 on this line.
>
> > and add the below to /etc/sysctl.conf
>
> >   net.ipv6.conf.all.forwarding = 1
> >   net.ipv6.conf.default.forwarding = 1
>
> > and through /proc i can see this
> >
> >   [root@centosv0 sysconfig]# cat
> /proc/sys/net/ipv6/conf/default/forwarding
> >   1
> >[root@centosv0 sysconfig]# cat /proc/sys/net/ipv6/conf/all/forwarding
> >1
>
> > and through command ifco

Re: [CentOS] RAID 6 - opinions

[Keith Keller]

On 2013-04-12, Miranda Hawarden-Ogata  wrote:
> RAID6 means you can handle 2 disk failures, but the third one will drop 
> your array, if I'm remembering correctly. And the larger the number of 
> disks, the higher the chance that you'll have disk failures...

Yes, and yes.  But different configurations of other RAID levels will
give you different levels of protection--not "better" or "worse",
because that needs to be evaluated in context.

For example, as has been noted, RAID6 can lose up to two drives, and the
third lost drive loses the array [0].  A 12-drive RAID10, with six
two-drive RAID1 components, can lose up to six drives, but only the
right six drives--losing both drives of one RAID1 loses the entire
array.  On the other side of things, rebuilding a 12-drive RAID6 will
take much longer than rebuilding one RAID1 component of a RAID10.  And
as one more example, a 12-drive RAID50, with three four-drive RAID5
components, can lose up to three drives, one from each component, but
two drives from one RAID5 loses the array.  Rebuild times will be longer
than RAID10 but shorter than RAID6.  (There are also performance
questions, which I know little about.)

RAID6 is certainly the most efficient way, space-wise, to allocate
drives such that you can lose up to two drives before losing the array.
So if maximizing storage space is the primary concern, greater than
performance, RAID6 is likely the best choice.  But, as is often repeated
here, on the md RAID list, and elsewhere, ***RAID IS NOT A BACKUP
SOLUTION!!!***  If you care about your data you need to back it up
elsewhere.  Do *not* rely solely on RAID to keep your data safe!  All
sorts of bad things can happen: a flaky controller can cause filesystem
problems, and a badly defective controller can completely destroy the
array.  RAID allows you to tolerate some failure, but it can't save your
data from catastrophe.

--keith

[0] "loses the array" here means that it won't be mountable without
some sort of expensive drive recovery process.


-- 
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Re: [CentOS] centos 6.3 ipv6 default gateway

[Michael H. Warfield]

On Fri, 2013-04-12 at 09:28 +0800, Jaze Lee wrote:
> 2013/4/12 Michael H. Warfield 
> 
> > Hello,
> >
> > I may be totally off base here but...
> >
> > On Thu, 2013-04-11 at 18:06 +0800, Jaze Lee wrote:
> > > hello,
> > >i met a problem in configuratiion of ipv6 gw in my box
> > > i install centos 6.3 (64 bit) on my boxs, which have four netcard.
> > > i use a straight-through cable to connect centosv0:netcard-2 and
> > > centosv1:netcard2
> > > the topology is this:
> > > client c(windows xp) <-->centosv0:netcard-3 <--> centosv0:netcard-2 <--->
> > > centosv1:netcard-2 <>centosv1:netcard-2  <---> client d (backtrack r2
> > > 32)
> > > 1:2:3:4::2/64  1:2:3:4::1/64   1:2:3::4/64
> > >   1:2:3::5/64 1:2:3:5::1/64
> > >  1:2:3:5::2/64
> >
> > Surely, I hope you jest with those numbers.  You are not allowed to pick
> > numbers out of the air and just use them, even if it's for private use.
> > There are specific blocks of addresses for specific uses and assigned
> > "scopes" and all the "private use" addresses are in blocks very high up
> > in the address space beginning with fc or fd.  If those are literally
> > the addresses you used, they will not work and I would expect them to
> > give you all sorts of grief at some point or another.
> >
> > > what i want to do is set default gw on centosv0 to centosv1
> >
> > I take it "centosv0"  and "centosv1" are configured for ipv6 forwarding?
> > You didn't provide the information on that.  There are some gotcha's in
> > there with default routing on a router (basically there is no such
> > thing) and the router needs to be set up properly for both routing and
> > its routes.  But I don't think that's your problem you're describing
> > down below.
> >
> > > i configure /etc/sysconfig/network-scripts/ifconfig-eth2  (centosv0) as
> > this
> > > DEVICE="eth2"
> > > BOOTPROTO=static
> > > HWADDR="60:A4:4C:23:2F:6F"
> > > NM_CONTROLLED="yes"
> > > ONBOOT="yes"
> > > TYPE="Ethernet"
> > > #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> > > IPV6INIT=yes
> > > IPV6ADDR=1:2:3::4
> >  ^^ You didn't specify a netmask here (default /128).
> >
> > > IPV6_DEFAULTGW=1:2:3::5
> >   Technically not on your interface's network
> > (/128)
> >
> > > and i also configure /etc/sysconfig/network to this:
> > > NETWORKING=yes
> > > HOSTNAME=centosv0
> > > NETWORKING_IPV6=yes
> > > IPV6_AUTOCONF=no
> >
> > For forwarding...
> >
> > In that file you're also going to need:
> >
> > IPV6FORWARDING=yes
> >
> > You may also need to add lines to /etc/sysctl.conf (I've needed in the
> > past on Fedora):
> >
> > net.ipv6.conf.all.forwarding = 1
> > net.ipv6.conf.default.forwarding = 1
> >
> > But those aren't your problem with this...
> >
> > > but i met an error:
> > > Bringing up interface eth2:  WARN : [ipv6_add_route] Unknown error
> >
> > I'm not totally sure if this is because you didn't specify a prefix
> > length on your IPV6ADDR line or the fact that it then conflicted with
> > your IPV6_DEFAULTGW which would not have been on 1:2:3::4/128 or if it
> > was because you choose and illegal IPv6 prefix or if it was a
> > combination of all of them.  The "WARN: [ipv6_add_route] Unknown error"
> > makes me suspicious because your default gatway conflicts with your
> > interface network definition (because you didn't specify the prefix size
> > and it defaulted to /128) and the kernel has no way to route it out any
> > interface.  IAC...  You won't be able to use a default route on a router
> > anyways (more below).
> >
> > > i do not know how why,and can some one gives me some suggestion?
> > > thanks a lot.
> >
> > If those were literally the addresses you used, It may be an address
> > that's in an illegal scope.
> 
>   i test those ipv6 address on ubuntu 12.04, and it is ok. But now, we
> should change system to Centos 6.3.
>   And i add all the stuff that i miss. One machine is configured like this:
> 
>  [root@centosv0 sysconfig]# cat /etc/sysconfig/network-scripts/ifcfg-eth2
> DEVICE="eth2"
> BOOTPROTO=static
> HWADDR="60:A4:4C:23:2F:6F"
> NM_CONTROLLED="yes"
> ONBOOT="yes"
> TYPE="Ethernet"
> #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> IPV6INIT=yes
> IPV6ADDR=1:2:3::4/64
> IPV6_DEFAULTGW=1:2:3::5/64
 ^^^  You do NOT need the /64 on this line.

> and add the below to /etc/sysctl.conf

>   net.ipv6.conf.all.forwarding = 1
>   net.ipv6.conf.default.forwarding = 1

> and through /proc i can see this
> 
>   [root@centosv0 sysconfig]# cat /proc/sys/net/ipv6/conf/default/forwarding
>   1
>[root@centosv0 sysconfig]# cat /proc/sys/net/ipv6/conf/all/forwarding
>1

> and through command ifconfig i can see this

> eth1  Link encap:Ethernet  HWaddr 60:A4:4C:23:2F:6E
>   inet6 addr: 1:2:3:4::1/64 Scope:Global  --->
> subnet
>   inet6 addr: fe80::62a4:4cff:fe23:2f6e/64 Scope:Link
>   UP BROADCAST RUNNING MULTICAST  MTU

Re: [CentOS] RAID 6 - opinions

[Miranda Hawarden-Ogata]

On 2013/04/11 10:36 AM, Joseph Spenner wrote:
> 
>   From: John R Pierce 
> To: centos@centos.org
> Sent: Thursday, April 11, 2013 1:24 PM
> Subject: Re: [CentOS] RAID 6 - opinions
>   
>
> On 4/11/2013 12:30 PM, m.r...@5-cent.us wrote:
>>> Ok, listening to all of this, I've also been in touch with a tech from the
>>> vendor*, who had a couple of suggestions: first, two RAID sets with two
>>> global hot spares.
>
> I would test how long a drive rebuild takes on a 20 disk RAID6.I
> suspect, very long, like over 24 hours, assuming a fast controller and
> sufficient channel bandwidth.
>
> 
>
> But isn't that one of the benefits of RAID6?  (not much degraded/latency 
> effect during a rebuild, less impact on performance during rebuild, so longer 
> times are acceptable?)
>
> __
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Besides performance, the longer your rebuild takes, the more vulnerable 
you are to additional disk failure taking out your array. We've lost 
arrays that way in the past, pre-RAID6, lost two disks within a 6-hour 
period, and there went the array since the rebuild wasn't complete. 
RAID6 means you can handle 2 disk failures, but the third one will drop 
your array, if I'm remembering correctly. And the larger the number of 
disks, the higher the chance that you'll have disk failures...

Thanks!
Miranda

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Re: [CentOS] centos 6.3 ipv6 default gateway

[Jaze Lee]

2013/4/12 Michael H. Warfield 

> Hello,
>
> I may be totally off base here but...
>
> On Thu, 2013-04-11 at 18:06 +0800, Jaze Lee wrote:
> > hello,
> >i met a problem in configuratiion of ipv6 gw in my box
> > i install centos 6.3 (64 bit) on my boxs, which have four netcard.
> > i use a straight-through cable to connect centosv0:netcard-2 and
> > centosv1:netcard2
> > the topology is this:
> > client c(windows xp) <-->centosv0:netcard-3 <--> centosv0:netcard-2 <--->
> > centosv1:netcard-2 <>centosv1:netcard-2  <---> client d (backtrack r2
> > 32)
> > 1:2:3:4::2/64  1:2:3:4::1/64   1:2:3::4/64
> >   1:2:3::5/64 1:2:3:5::1/64
> >  1:2:3:5::2/64
>
> Surely, I hope you jest with those numbers.  You are not allowed to pick
> numbers out of the air and just use them, even if it's for private use.
> There are specific blocks of addresses for specific uses and assigned
> "scopes" and all the "private use" addresses are in blocks very high up
> in the address space beginning with fc or fd.  If those are literally
> the addresses you used, they will not work and I would expect them to
> give you all sorts of grief at some point or another.
>
> > what i want to do is set default gw on centosv0 to centosv1
>
> I take it "centosv0"  and "centosv1" are configured for ipv6 forwarding?
> You didn't provide the information on that.  There are some gotcha's in
> there with default routing on a router (basically there is no such
> thing) and the router needs to be set up properly for both routing and
> its routes.  But I don't think that's your problem you're describing
> down below.
>
> > i configure /etc/sysconfig/network-scripts/ifconfig-eth2  (centosv0) as
> this
> > DEVICE="eth2"
> > BOOTPROTO=static
> > HWADDR="60:A4:4C:23:2F:6F"
> > NM_CONTROLLED="yes"
> > ONBOOT="yes"
> > TYPE="Ethernet"
> > #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> > IPV6INIT=yes
> > IPV6ADDR=1:2:3::4
>  ^^ You didn't specify a netmask here (default /128).
>
> > IPV6_DEFAULTGW=1:2:3::5
>   Technically not on your interface's network
> (/128)
>
> > and i also configure /etc/sysconfig/network to this:
> > NETWORKING=yes
> > HOSTNAME=centosv0
> > NETWORKING_IPV6=yes
> > IPV6_AUTOCONF=no
>
> For forwarding...
>
> In that file you're also going to need:
>
> IPV6FORWARDING=yes
>
> You may also need to add lines to /etc/sysctl.conf (I've needed in the
> past on Fedora):
>
> net.ipv6.conf.all.forwarding = 1
> net.ipv6.conf.default.forwarding = 1
>
> But those aren't your problem with this...
>
> > but i met an error:
> > Bringing up interface eth2:  WARN : [ipv6_add_route] Unknown error
>
> I'm not totally sure if this is because you didn't specify a prefix
> length on your IPV6ADDR line or the fact that it then conflicted with
> your IPV6_DEFAULTGW which would not have been on 1:2:3::4/128 or if it
> was because you choose and illegal IPv6 prefix or if it was a
> combination of all of them.  The "WARN: [ipv6_add_route] Unknown error"
> makes me suspicious because your default gatway conflicts with your
> interface network definition (because you didn't specify the prefix size
> and it defaulted to /128) and the kernel has no way to route it out any
> interface.  IAC...  You won't be able to use a default route on a router
> anyways (more below).
>
> > i do not know how why,and can some one gives me some suggestion?
> > thanks a lot.
>
> If those were literally the addresses you used, It may be an address
> that's in an illegal scope.

  i test those ipv6 address on ubuntu 12.04, and it is ok. But now, we
should change system to Centos 6.3.
  And i add all the stuff that i miss. One machine is configured like this:

 [root@centosv0 sysconfig]# cat /etc/sysconfig/network-scripts/ifcfg-eth2
DEVICE="eth2"
BOOTPROTO=static
HWADDR="60:A4:4C:23:2F:6F"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
#UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
IPV6INIT=yes
IPV6ADDR=1:2:3::4/64
IPV6_DEFAULTGW=1:2:3::5/64

and add the below to /etc/sysctl.conf

  net.ipv6.conf.all.forwarding = 1
  net.ipv6.conf.default.forwarding = 1

and through /proc i can see this

  [root@centosv0 sysconfig]# cat /proc/sys/net/ipv6/conf/default/forwarding
  1
   [root@centosv0 sysconfig]# cat /proc/sys/net/ipv6/conf/all/forwarding
   1

and through command ifconfig i can see this

eth1  Link encap:Ethernet  HWaddr 60:A4:4C:23:2F:6E
  inet6 addr: 1:2:3:4::1/64 Scope:Global  --->
subnet
  inet6 addr: fe80::62a4:4cff:fe23:2f6e/64 Scope:Link
  UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
  RX packets:0 errors:0 dropped:0 overruns:0 frame:0
  TX packets:22 errors:0 dropped:0 overruns:0 carrier:0
  collisions:0 txqueuelen:1000
  RX bytes:0 (0.0 b)  TX bytes:2028 (1.9 KiB)
  Interrupt:17 Memory:dc30-dc32

eth2  Link encap:Ethernet  HWaddr 60:A4:4C:23:2F:6F
  inet6 addr: 1:2:3:

Re: [CentOS] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 5:04 PM, David C. Miller wrote:
> The LSI 9200's I use are nothing more than a dumb $300 host bus adapter. No 
> RAID levels or special features. I prefer to NOT use hardware RAID 
> controllers when I can. With a generic HBA the hard drives are seen raw to 
> the OS. You can use smartctl to poll and test the drives just like they were 
> connected to a generic SATA bus on the motherboard. The tools built into 
> Linux(smartd & md) are better suited and more flexible at reporting problems 
> and handling every level of RAID. It also makes migrating the array to 
> another system trivial. I don't have to worry about finding the exact same 
> RAID controller. Just a no frills SAS/SATA HBA will do.

yeah, until a disk fails on a 40 disk array and the chassis LEDs on the 
backplane don't light up to indicate which disk it is and your 
operations monkey pulls the wrong one and crash the whole raid.

have fun with that!

if you can figure out how to get the drive backplane status LEDs to work 
on Linux with a 'dumb' controller plugged into a drive backplane, PLEASE 
WRITE IT UP ON A WIKI SOMEWHERE!!!   everything I've seen leaves this 
gnarly task as an exercise to the reader. With a card like a 9261-8i, it 
just works automatically.

also, hardware raid controllers WITH battery backed (or flash backed) 
cache can greatly speed up small block write operations like directory 
entry creates, database writes, etc.



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Re: [CentOS] How to change 'fstab' when you cannot boot the machine?

[zGreenfelder]

or while it's in single user mode with the read only /; do a mount -o
remount / to get the filesystem into read write, edit your fstab file
and reboot.

On Thu, Apr 11, 2013 at 7:36 PM, Jason T. Slack-Moehrle
 wrote:
> Hello All,
>
> So My Drobo finished formatting and I added an entry to fstab for it and
> now I cannot boot the machine. I get an error about
>
> fsck.ext3: is a directory while trying to open /drobo
> and then a mention of a valid super block
>
> I had mounted the Drobo as /drobo and in 'fstab' I copied the line for '/'
> changing to ext3 where it was ext4.
>
> I have made a mistake
>
> I cannot fix it because trying to edit fstab results in a "read only file
> system message"
>
> Can anyone help me learn how to recover?
>
> Jason
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Re: [CentOS] RAID 6 - opinions

[David C. Miller]

- Original Message -
> From: "Keith Keller" 
> To: centos@centos.org
> Sent: Thursday, April 11, 2013 4:34:20 PM
> Subject: Re: [CentOS] RAID 6 - opinions
> 
> On 2013-04-11, David C. Miller  wrote:
> >
> > Just for reference, I have a 24 x 2TB SATAIII using CentOS 6.4
> > Linux MD RAID6 with two of those 24 disks as hotspares. The drives
> > are in a Supermicro external SAS/SATA box connected to another
> > Supermicro 1U computer with an i3-2125 CPU @ 3.30GHz and 16GB ram.
> > The connection is via a 6Gbit mini SAS cable to an LSI 9200 HBA.
> > Before I deployed it into production I tested how long it would
> > take to rebuild the raid from one of the hot spares and it took a
> > little over 9 hours.
> 
> I did a similar test on a 3ware controller.  Apparently those cards
> have
> a feature that allows the controller to remember which sectors on the
> disks it has written, so that on a rebuild it only reexamines those
> sectors.  This greatly reduces rebuild time on a mostly empty array,
> but
> it means that a good test would almost fill the array, then attempt a
> rebuild.  I definitely saw a difference in rebuild times as I filled
> the
> array.  (In 3ware/LSI world this is sometimes called "rapid RAID
> recovery".)
> 
> In checking my archives, it looks like a rebuild on an almost full
> 50TB
> array (24 disks) took about 16 hours.  That's still pretty
> respectable.
> I didn't repeat the experiment, unfortunately.
> 
> I don't know if your LSI controller has a similar feature, but it's
> worth investigating.
> 
> --keith
> 

The LSI 9200's I use are nothing more than a dumb $300 host bus adapter. No 
RAID levels or special features. I prefer to NOT use hardware RAID controllers 
when I can. With a generic HBA the hard drives are seen raw to the OS. You can 
use smartctl to poll and test the drives just like they were connected to a 
generic SATA bus on the motherboard. The tools built into Linux(smartd & md) 
are better suited and more flexible at reporting problems and handling every 
level of RAID. It also makes migrating the array to another system trivial. I 
don't have to worry about finding the exact same RAID controller. Just a no 
frills SAS/SATA HBA will do.

David.
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Re: [CentOS] How to change 'fstab' when you cannot boot the machine?

[Jason T. Slack-Moehrle]

> why not try it out?
>
> as said:
> ANY linux with a terminal is enough to mount the rootfs
> and edit /ect/fstab with vi or whatever
>
> P.S: use the mailing-list instead off-list replies
>
> Am 12.04.2013 01:42, schrieb Jason T. Slack-Moehrle:
> > If I have a CentOS 6.4 DVD is that the 'Rescue installed system' menu
> option?
>

Sorry for the personal reply. An oversight.

My hesitation with the 'Rescue installed system' sort of reminds me of
Windows where this option will go and blindly copy new versions of files to
a system to get it to boot. I wasn't sure what would happen if I selected
this option from the DVD.

I will try it now.
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Re: [CentOS] How to change 'fstab' when you cannot boot the machine?

[Frank Cox]

On Thu, 11 Apr 2013 16:36:44 -0700
Jason T. Slack-Moehrle wrote:
> I have made a mistake
> 
> I cannot fix it because trying to edit fstab results in a "read only file
> system message"
> 
> Can anyone help me learn how to recover?

Boot from a recovery disk (live CD, whatever) and fix the problem.


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[CentOS] How to change 'fstab' when you cannot boot the machine?

[Jason T. Slack-Moehrle]

Hello All,

So My Drobo finished formatting and I added an entry to fstab for it and
now I cannot boot the machine. I get an error about

fsck.ext3: is a directory while trying to open /drobo
and then a mention of a valid super block

I had mounted the Drobo as /drobo and in 'fstab' I copied the line for '/'
changing to ext3 where it was ext4.

I have made a mistake

I cannot fix it because trying to edit fstab results in a "read only file
system message"

Can anyone help me learn how to recover?

Jason
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Re: [CentOS] RAID 6 - opinions

[Keith Keller]

On 2013-04-11, David C. Miller  wrote:
>
> Just for reference, I have a 24 x 2TB SATAIII using CentOS 6.4 Linux MD RAID6 
> with two of those 24 disks as hotspares. The drives are in a Supermicro 
> external SAS/SATA box connected to another Supermicro 1U computer with an 
> i3-2125 CPU @ 3.30GHz and 16GB ram. The connection is via a 6Gbit mini SAS 
> cable to an LSI 9200 HBA. Before I deployed it into production I tested how 
> long it would take to rebuild the raid from one of the hot spares and it took 
> a little over 9 hours.

I did a similar test on a 3ware controller.  Apparently those cards have
a feature that allows the controller to remember which sectors on the
disks it has written, so that on a rebuild it only reexamines those
sectors.  This greatly reduces rebuild time on a mostly empty array, but
it means that a good test would almost fill the array, then attempt a
rebuild.  I definitely saw a difference in rebuild times as I filled the
array.  (In 3ware/LSI world this is sometimes called "rapid RAID
recovery".)

In checking my archives, it looks like a rebuild on an almost full 50TB
array (24 disks) took about 16 hours.  That's still pretty respectable.
I didn't repeat the experiment, unfortunately.

I don't know if your LSI controller has a similar feature, but it's
worth investigating.

--keith


-- 
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Re: [CentOS] RAID 6 - opinions

[David C. Miller]

- Original Message -
> From: "Reindl Harald" 
> To: "CentOS mailing list" 
> Cc: "David C. Miller" 
> Sent: Thursday, April 11, 2013 4:17:18 PM
> Subject: Re: [CentOS] RAID 6 - opinions
> 
> 
> 
> Am 12.04.2013 01:13, schrieb David C. Miller:
> > dd if=/dev/zero of=/backup/5GB.img count=5000 bs=1M
> > 5000+0 records in
> > 5000+0 records out
> > 524288 bytes (5.2 GB) copied, 10.8293 s, 484 MB/s
> 
> aha, you have 16 GB RAM, write 5 GB to the disk which
> is easily buffered into RAM and think this measures
> anything?
> 
> do the same with 32 GB instead 5 GB
> 
> 
Good call, I did not even think about that. Here is a 31GB file write. 

dd if=/dev/zero of=/backup/30GB.img count=3 bs=1M
3+0 records in
3+0 records out
3145728 bytes (31 GB) copied, 78.041 s, 403 MB/s

David.
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Re: [CentOS] RAID 6 - opinions

[David C. Miller]

- Original Message -
> From: "Joseph Spenner" 
> To: "CentOS mailing list" 
> Sent: Thursday, April 11, 2013 1:36:29 PM
> Subject: Re: [CentOS] RAID 6 - opinions
> 
> 
> 
> 
> 
>  From: John R Pierce 
> To: centos@centos.org
> Sent: Thursday, April 11, 2013 1:24 PM
> Subject: Re: [CentOS] RAID 6 - opinions
>  
> 
> On 4/11/2013 12:30 PM, m.r...@5-cent.us wrote:
> >> Ok, listening to all of this, I've also been in touch with a tech
> >> from the
> >> vendor*, who had a couple of suggestions: first, two RAID sets
> >> with two
> >> global hot spares.
> 
> 
> I would test how long a drive rebuild takes on a 20 disk RAID6.    I
> suspect, very long, like over 24 hours, assuming a fast controller
> and
> sufficient channel bandwidth.
> 

Just for reference, I have a 24 x 2TB SATAIII using CentOS 6.4 Linux MD RAID6 
with two of those 24 disks as hotspares. The drives are in a Supermicro 
external SAS/SATA box connected to another Supermicro 1U computer with an 
i3-2125 CPU @ 3.30GHz and 16GB ram. The connection is via a 6Gbit mini SAS 
cable to an LSI 9200 HBA. Before I deployed it into production I tested how 
long it would take to rebuild the raid from one of the hot spares and it took a 
little over 9 hours. I have two 15TB LVM's on it formatted EXT4 with the rest 
used for LVM snapshot space if needed. Using dd to write a large file to one of 
the partitions I see about 480MB/s. If I rsync from one partition to another I 
get just under 200MB/s. 

dd if=/dev/zero of=/backup/5GB.img count=5000 bs=1M
5000+0 records in
5000+0 records out
524288 bytes (5.2 GB) copied, 10.8293 s, 484 MB/s

David.
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Re: [CentOS] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 1:20 PM, m.r...@5-cent.us wrote:
> Followup comment: I created the two RAID sets, then started to create the
> volume sets... and realized I didn't know if it was*possible*, much less
> desirable, to have a volume set that spanned two RAID sets. Talked it over
> with my manager, and I redid it as three RAID sets, one volume set each.

sure.  throw all the RAIDs into a single LVM volume group, and then 
stripe 3 logical volumes's across that volume group


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Re: [CentOS] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 1:36 PM, Joseph Spenner wrote:
> But isn't that one of the benefits of RAID6?  (not much degraded/latency 
> effect during a rebuild, less impact on performance during rebuild, so longer 
> times are acceptable?)

trouble comes in 3s.



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Re: [CentOS] RAID 6 - opinions

[Joseph Spenner]

 From: John R Pierce 
To: centos@centos.org 
Sent: Thursday, April 11, 2013 1:24 PM
Subject: Re: [CentOS] RAID 6 - opinions
 

On 4/11/2013 12:30 PM, m.r...@5-cent.us wrote:
>> Ok, listening to all of this, I've also been in touch with a tech from the
>> vendor*, who had a couple of suggestions: first, two RAID sets with two
>> global hot spares.


I would test how long a drive rebuild takes on a 20 disk RAID6.    I 
suspect, very long, like over 24 hours, assuming a fast controller and 
sufficient channel bandwidth.



But isn't that one of the benefits of RAID6?  (not much degraded/latency effect 
during a rebuild, less impact on performance during rebuild, so longer times 
are acceptable?)

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Re: [CentOS] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 12:30 PM, m.r...@5-cent.us wrote:
> Ok, listening to all of this, I've also been in touch with a tech from the
> vendor*, who had a couple of suggestions: first, two RAID sets with two
> global hot spares.


I would test how long a drive rebuild takes on a 20 disk RAID6.I 
suspect, very long, like over 24 hours, assuming a fast controller and 
sufficient channel bandwidth.



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Re: [CentOS] RAID 6 - opinions

[m . roth]

m.r...@5-cent.us wrote:

> Ok, listening to all of this, I've also been in touch with a tech from the
> vendor*, who had a couple of suggestions: first, two RAID sets with two
> global hot spares.
>
> I've just spoken with my manager, and we're going with that, then one of
> the tech's other suggestions was three volume sets on top of the two RAID
> sets, so we'll have what look like three drives/LUNs of about 13+TB each.

Followup comment: I created the two RAID sets, then started to create the
volume sets... and realized I didn't know if it was *possible*, much less
desirable, to have a volume set that spanned two RAID sets. Talked it over
with my manager, and I redid it as three RAID sets, one volume set each.

Maybe the initialization will be done tomorrow 

 mark

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Re: [CentOS] centos 6.3 ipv6 default gateway

[Michael H. Warfield]

Slight Clarification on v6 addressing...

On Thu, 2013-04-11 at 15:38 -0400, Michael H. Warfield wrote:

> Those may be routed between your machines but may not be routed on the
> global net either as a source or destination address.  Your machines
> should also be given "link local" addresses which are valid only on that
> network segment.  They're in the fe80::/64 prefix.

That's "should" as in the kernel should already have assigned your
link-local v6 addresses to your interfaces.  You don't have to provide
them and I didn't mean to imply you needed to add them.

Generally, if I'm using static IPv6 addresses, I take that link local
address and replace the "fe80::" with the network prefix I'm assigning
and leave the lower bits the same.  That way it has the same address as
would be assigned by stateless autoconf generated from router
advertisements from a router.

On Linux routers, you would use either zebra from the quagga package or
radvd to provide router advertisements out to your clients and you'll
probably need to add that to get the end clients to self configure
properly.

Regards,
Mike
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Re: [CentOS] centos 6.3 ipv6 default gateway

[Michael H. Warfield]

Hello,

I may be totally off base here but...

On Thu, 2013-04-11 at 18:06 +0800, Jaze Lee wrote:
> hello,
>i met a problem in configuratiion of ipv6 gw in my box
> i install centos 6.3 (64 bit) on my boxs, which have four netcard.
> i use a straight-through cable to connect centosv0:netcard-2 and
> centosv1:netcard2
> the topology is this:
> client c(windows xp) <-->centosv0:netcard-3 <--> centosv0:netcard-2 <--->
> centosv1:netcard-2 <>centosv1:netcard-2  <---> client d (backtrack r2
> 32)
> 1:2:3:4::2/64  1:2:3:4::1/64   1:2:3::4/64
>   1:2:3::5/64 1:2:3:5::1/64
>  1:2:3:5::2/64

Surely, I hope you jest with those numbers.  You are not allowed to pick
numbers out of the air and just use them, even if it's for private use.
There are specific blocks of addresses for specific uses and assigned
"scopes" and all the "private use" addresses are in blocks very high up
in the address space beginning with fc or fd.  If those are literally
the addresses you used, they will not work and I would expect them to
give you all sorts of grief at some point or another.

> what i want to do is set default gw on centosv0 to centosv1

I take it "centosv0"  and "centosv1" are configured for ipv6 forwarding?
You didn't provide the information on that.  There are some gotcha's in
there with default routing on a router (basically there is no such
thing) and the router needs to be set up properly for both routing and
its routes.  But I don't think that's your problem you're describing
down below.

> i configure /etc/sysconfig/network-scripts/ifconfig-eth2  (centosv0) as this
> DEVICE="eth2"
> BOOTPROTO=static
> HWADDR="60:A4:4C:23:2F:6F"
> NM_CONTROLLED="yes"
> ONBOOT="yes"
> TYPE="Ethernet"
> #UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
> IPV6INIT=yes
> IPV6ADDR=1:2:3::4
 ^^ You didn't specify a netmask here (default /128).

> IPV6_DEFAULTGW=1:2:3::5
  Technically not on your interface's network (/128)

> and i also configure /etc/sysconfig/network to this:
> NETWORKING=yes
> HOSTNAME=centosv0
> NETWORKING_IPV6=yes
> IPV6_AUTOCONF=no

For forwarding...

In that file you're also going to need:

IPV6FORWARDING=yes

You may also need to add lines to /etc/sysctl.conf (I've needed in the
past on Fedora):

net.ipv6.conf.all.forwarding = 1
net.ipv6.conf.default.forwarding = 1

But those aren't your problem with this...

> but i met an error:
> Bringing up interface eth2:  WARN : [ipv6_add_route] Unknown error

I'm not totally sure if this is because you didn't specify a prefix
length on your IPV6ADDR line or the fact that it then conflicted with
your IPV6_DEFAULTGW which would not have been on 1:2:3::4/128 or if it
was because you choose and illegal IPv6 prefix or if it was a
combination of all of them.  The "WARN: [ipv6_add_route] Unknown error"
makes me suspicious because your default gatway conflicts with your
interface network definition (because you didn't specify the prefix size
and it defaulted to /128) and the kernel has no way to route it out any
interface.  IAC...  You won't be able to use a default route on a router
anyways (more below).

> i do not know how why,and can some one gives me some suggestion?
> thanks a lot.

If those were literally the addresses you used, It may be an address
that's in an illegal scope.  IPv6 does not behave quite like IPv4 does
and you need to know what some of these blocks of addresses do and what
their scope is.

"Local" IPv6 unicast addresses begin with the prefix fc00::/7 and there
are recommended procedures for assigning subnets out of them and
choosing network prefixes...

http://www.ietf.org/rfc/rfc4193.txt

Those may be routed between your machines but may not be routed on the
global net either as a source or destination address.  Your machines
should also be given "link local" addresses which are valid only on that
network segment.  They're in the fe80::/64 prefix.

Global addresses are in the 2000::/3 block.  If you are using a Linux
system as an IPv6 router, the kernel is going to disable the default
route (::/0), preventing non-global addresses from routing.  You'll have
to add appropriate routes for all your "local" (fc00::/7) subnets and
also provide a global unicast default route using 2000::/3 on the
routers.

Don't try to do your setup above with the two routers pointing default
routes at each other.  Point specific static routes for each subnet
behind each respective opposite router.

Wikipedia has a rundown on the various address blocks and formats:

http://en.wikipedia.org/wiki/IPv6_address

Local addresses in particular are described here:

http://en.wikipedia.org/wiki/Unique_local_address

Anything in 1::/16 (if that's what you're doing) is going to be illegal
afaik as it's not in an assigned block and scope.  It should reject it
as being unroutable or having a non-valid scope.

Certain addresses below 2000::/3 are used for compatibility purposes.

::a.b.c.d use to 

Re: [CentOS] RAID 6 - opinions

[m . roth]

John R Pierce wrote:
> On 4/11/2013 8:36 AM, m.r...@5-cent.us wrote:
>> I'm setting up this huge RAID 6 box. I've always thought of hot spares,
>> but I'm reading things that are comparing RAID 5 with a hot spare to
>> RAID 6, implying that the latter doesn't need one. I*certainly*  have
enough
>> drives to spare in this RAID box: 42 of 'em, so two questions: should I
>> assign one or more hot spares, and, if so, how many?
>
> John's First Rule of Raid.   when a drive fails 2-3 years downstream,
> replacements will be unavailable.  If you had bought cold spares and
> stored them, odds are too high they will be lost when you need them.
>
> John's Second Rule of Raid.  No single raid should be much over 10-12
> disks, or the rebuild times become truly hellacious.
>
> John's Third Rule of Raid.  allow 5-10% hot spares.
>
> so, with 42 disks, 10% would be ~4 spares, which leaves 38.  5% would be
> 2 spares, allowing 40 disks.

> I did some testing of very large raids using LSI Logic  9261-8i MegaRAID
> SAS2 cards driving 36 3TB SATA3 disks.  With 3 x 11 disk RAID6 (and 3
> hot spares), a failed disk took about 12 hours to restripe with the
> rebuilding set to medium priority, and the raid essentially idle.
>
> if you're using XFS on this very large file system (which I *would*
> recommend), do be sure to use a LOT of ram, like 48GB...   while regular
> operations might not need it, XFS's fsck process is fairly memory
> intensive on a very large volume with millions of files.

Ok, listening to all of this, I've also been in touch with a tech from the
vendor*, who had a couple of suggestions: first, two RAID sets with two
global hot spares.

I've just spoken with my manager, and we're going with that, then one of
the tech's other suggestions was three volume sets on top of the two RAID
sets, so we'll have what look like three drives/LUNs of about 13+TB each.

All your comments were very appreciated, and gave me a lot more confidence
in this setup. We will be using ext4, btw - I don't get to try out XFS on
this $$ baby.

 mark

* Unpaid plug: we bought this from AC&NC: their own price was cheaper than
either of the two resellers I spoke to (three quotes required), they seem
pretty hungry (but have been around a while, given the number of old boxes
we have), and they respond *very* quickly to problems for support.

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Re: [CentOS] RAID 6 - opinions

[Keith Keller]

On 2013-04-11, Joseph Spenner  wrote:
>>From: "m.r...@5-cent.us" 
>
>>To: CentOS mailing list  
>>Sent: Thursday, April 11, 2013 8:36 AM
>>Subject: [CentOS] RAID 6 - opinions
>  
>>
>>I'm setting up this huge RAID 6 box. I've always thought of hot spares,
>>but I'm reading things that are comparing RAID 5 with a hot spare to RAID
>>6, implying that the latter doesn't need one. I *certainly* have enough
>>drives to spare in this RAID box: 42 of 'em, so two questions: should I
>>assign one or more hot spares, and, if so, how many?

As another poster mentioned, I'd even break this up into multiple RAID6
arrays.  One big honking 42 drive array, if they're large disks, will
take forever to rebuild after a failure.

> As far as having a spare disk on a RAID6, I'd say it's not necessary.  As 
> long as you have some mechanism in place to inform you if/when a disk fails, 
> you'll not suffer any performance hit.

With this many drives, I'd designate at least one as a global spare
anyway.  Yes, you lose some capacity, but you have even more cushion if,
say, you're out of town for a week, a drive fails, and your backup
person is sick.  One possible configuration is to create three RAID6
arrays with 11 drives each (or one or two with 12 instead), and group
them using LVM.  You could also simply create one RAID6 with the capacity
you need for the next few months, then create new arrays and add them to
your volume group as you need them.  This has the added bonus that you
look like a genius for deploying new capacity so quickly.  :)  Recently
I acquired a half-empty storage array, so that I can add larger drives as
they become available instead of being tied to drive sizes of today.

> A RAID5 with a hot spare isn't really the same as a RAID6.  For those not 
> familiar with this, a RAID5 in degraded mode (after it lost a disk) will 
> suffer a performance hit, as well as while it rebuilds from a hot spare.  A 
> RAID6 after losing a disk will not suffer.

I seem to remember reading on the linux RAID mailing list that, at least
for linux md RAID6 (which the OP may not be using), performance on a RAID6
with one missing drive is slightly worse than optimal RAID5.  I could be
wrong however, and perhaps a hardware RAID controller doesn't have this
deficiency.

--keith



-- 
kkel...@wombat.san-francisco.ca.us


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Re: [CentOS] RAID 6 - opinions

[John R Pierce]

On 4/11/2013 8:36 AM, m.r...@5-cent.us wrote:
> I'm setting up this huge RAID 6 box. I've always thought of hot spares,
> but I'm reading things that are comparing RAID 5 with a hot spare to RAID
> 6, implying that the latter doesn't need one. I*certainly*  have enough
> drives to spare in this RAID box: 42 of 'em, so two questions: should I
> assign one or more hot spares, and, if so, how many?

John's First Rule of Raid.   when a drive fails 2-3 years downstream, 
replacements will be unavailable.  If you had bought cold spares and 
stored them, odds are too high they will be lost when you need them.

John's Second Rule of Raid.  No single raid should be much over 10-12 
disks, or the rebuild times become truly hellacious.

John's Third Rule of Raid.  allow 5-10% hot spares.

so, with 42 disks, 10% would be ~4 spares, which leaves 38.  5% would be 
2 spares, allowing 40 disks.

40 divided by 4 == 10.   You could format that as 10 raid6's, and stripe 
those (aka raid6+0 or raid60), and use 2 hot spares.
Alternately, 3*13 == 39, leaving three hotspares, so 3 stripes of 13 
disks with 3 hot spares is an alternative.

I did some testing of very large raids using LSI Logic  9261-8i MegaRAID 
SAS2 cards driving 36 3TB SATA3 disks.  With 3 x 11 disk RAID6 (and 3 
hot spares), a failed disk took about 12 hours to restripe with the 
rebuilding set to medium priority, and the raid essentially idle.

if you're using XFS on this very large file system (which I *would* 
recommend), do be sure to use a LOT of ram, like 48GB...   while regular 
operations might not need it, XFS's fsck process is fairly memory 
intensive on a very large volume with millions of files.

-- 
john r pierce  37N 122W
somewhere on the middle of the left coast

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Re: [CentOS] Cluster SW

[Digimer]

On 04/11/2013 06:35 AM, Woehrle Hartmut SBB CFF FFS (Extern) wrote:
>>   Hi,
>>   How to download  Cluster SW and how to configure clustering in CentOS.
>> With Regards and  good wishes.
>>
>> V.SANTOSH
>
> What do you want to cluster (disks, services, data,...)
> How (failover, loadbalancing, master-slave,...)
>
> Hartmut

As Harmut asked; You need to share more about your goals before anyone 
can give you good advice. Assuming you are looking for a 
High-Availability Cluster (HAC) instead of a High-Performance Cluster (HPC);

Under CentOS, you have two primary options;

* The officially supported (by Red Hat) HA cluster stack is corosync + 
cman + rgmanager (commonly called simply "rhcs")

* The next-generation cluster stack (believe to replace cman + rgmanager 
in RHEL / CentOS 7) is corosync + pacemaker (commonly called simply 
"pacemaker" or "pcmk").

Personally, I use rhcs.

For any further advice, you need to share more first.

Cheers

-- 
Digimer
Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without 
access to education?
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Re: [CentOS] How to determine why a server is not responding

[Dale Dellutri]

On Thu, Apr 11, 2013 at 10:59 AM, nan del bosc  wrote:

> ...
> This is a Virtual Server from 1and1, I cannot access the BIOS...
>
> any other idea?
>

If this is a virtual server, the actual hardware may just be running
other virtual servers and you're not getting any resources.  If that's
true, nothing you do from your server will help you.  You'll need to
get system stats from the actual hardware provider.

Sounds like the hardware is over-committed.  Do you have some
kind of service guarantee?

-- 
Dale Dellutri
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Re: [CentOS] RAID 6 - opinions

[Digimer]

On 04/11/2013 11:36 AM, m.r...@5-cent.us wrote:
> I'm setting up this huge RAID 6 box. I've always thought of hot spares,
> but I'm reading things that are comparing RAID 5 with a hot spare to RAID
> 6, implying that the latter doesn't need one. I *certainly* have enough
> drives to spare in this RAID box: 42 of 'em, so two questions: should I
> assign one or more hot spares, and, if so, how many?
>
> mark

I was building a home NAS over the holidays and had the same question 
(well, not hot spare, but 5 vs. 6). A good friend on mine pointed me to 
the following article;

http://www.zdnet.com/blog/storage/why-raid-5-stops-working-in-2009/162

I was using 6x 3 TB drives, so I decided to opt for RAID 6. About a 
month ago, a drive cacked out and I was *very* relieved to know that I 
was covered until I replaced the disk and it finished rebuilding.

If you have 42 disks, I'd not even think twice and I would use RAID 
level 6. If fact, with such a large number, I'd almost be tempted to 
break it into two separate RAID level 6 arrays and use something like 
LVM to pool their space, just to hedge my bets.

-- 
Digimer
Papers and Projects: https://alteeve.ca/w/
What if the cure for cancer is trapped in the mind of a person without 
access to education?
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Re: [CentOS] How to determine why a server is not responding

[Kai Schaetzl]

Nan del bosc wrote on Thu, 11 Apr 2013 17:59:58 +0200:

> This is a Virtual Server from 1and1,

You should have said this in the beginning!
Can you be sure that this is a standard CentOS and not a version catered 
by the provider? It may just be a problem with the virtualizing software. 
You should talk to them. They also have means to access it in this hanging 
state from the host machine that you don't have.

Kai


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Re: [CentOS] How to determine why a server is not responding

[m . roth]

nan del bosc wrote:
> Thank's for your quick answer!
>
> I can't use ipmi in this machine...
>

> # modprobe ipmi_si
> FATAL: Error inserting ipmi_si
> (/lib/modules/2.6.18-194.26.1.el5xen/kernel/drivers/char/ipmi/ipmi_si.ko):
> No such device

Um, no: yum install OpenIPMI
service ipmi start
ll /dev/ipmi0.

> This is a Virtual Server from 1and1, I cannot access the BIOS...

Wait - this is hosted, not something you can lay your hands on? In that
case, you need to call the hosting provider and complain.

   mark

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Re: [CentOS] How to determine why a server is not responding

[Alexander Dalloz]

Am 11.04.2013 17:36, schrieb nan del bosc:
> Hi to all!
> 
> We're using CentOS 5.5 64bits for our Plesk 11.

That's insane! Why on earth do you run a 2,5 years old unpatched public
system? You are asking for trouble and innocent third will be the
victims of your hacked system.

> This week we had the following problem 3 times...
> 
> Suddenly, the server stops responding in all services (SSH, Apache,
> Postfix, ...) but ping works!
> 
> After wait a few minutes (or 2 hours some times) the server continues
> unresponsive until we reboot. After reboot we search on /var/log/messages
> but cannot find useful information...
> 
> Apr 11 14:56:05 s1 postfix/smtpd[8263]: SQL engine 'intentionally disabled'
> not supported
> Apr 11 14:56:05 s1 postfix/smtpd[8263]: auxpropfunc error no mechanism
> available
> Apr 11 14:56:42 s1 postfix/smtpd[8370]: SQL engine 'intentionally disabled'
> not supported
> Apr 11 14:56:42 s1 postfix/smtpd[8370]: auxpropfunc error no mechanism
> available
> Apr 11 14:56:47 s1 postfix/smtpd[8391]: SQL engine 'intentionally disabled'
> not supported
> Apr 11 14:56:47 s1 postfix/smtpd[8391]: auxpropfunc error no mechanism
> available
> Apr 11 14:56:47 s1 postfix/smtpd[8392]: SQL engine 'intentionally disabled'
> not supported
> Apr 11 14:56:47 s1 postfix/smtpd[8392]: auxpropfunc error no mechanism
> available
> Apr 11 16:55:42 s1 syslogd 1.4.1: restart.
> Apr 11 16:55:42 s1 kernel: klogd 1.4.1, log source = /proc/kmsg started.
> Apr 11 16:55:42 s1 kernel: Bootdata ok (command line is ro root=/dev/xvda1
> console=xvc0 console=hvc0 xencons=hvc)
> Apr 11 16:55:42 s1 kernel: Linux version 2.6.18-194.26.1.el5xen (
> mockbu...@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat
> 4.1.2-48)) #1 SMP Tue Nov 9 13:35:30 EST 2010

That's a Xen Domain. So IPMI, as suggested by others, will not work.

> Apr 11 16:55:42 s1 kernel: BIOS-provided physical RAM map:
> Apr 11 16:55:42 s1 kernel:  Xen:  - 8000
> (usable)
> Apr 11 16:55:42 s1 kernel: No mptable found.
> Apr 11 16:55:42 s1 kernel: Built 1 zonelists.  Total pages: 524288
> Apr 11 16:55:42 s1 kernel: Kernel command line: ro root=/dev/xvda1
> console=xvc0 console=hvc0 xencons=hvc

[ ... ]

> What can we do? what can we test?

First, update your system to the latest 5.9 + updates!

Talk to your hoster. If your Xen VM has issues other guests on the same
hardware may have too. Or another VM on the hosts consumes so much
resources that your VM does not respond any longer.

[ ... ]

> Thank's!
> 
> --
> ---
> Salut!

Alexander

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Re: [CentOS] How to determine why a server is not responding

[Александр Кириллов]

> We're using CentOS 5.5 64bits for our Plesk 11.
> 
> This week we had the following problem 3 times...
> 
> Suddenly, the server stops responding in all services (SSH, Apache,
> Postfix, ...) but ping works!
> 
> After wait a few minutes (or 2 hours some times) the server continues
> unresponsive until we reboot. After reboot we search on 
> /var/log/messages
> but cannot find useful information...

...

> 
> What can we do? what can we test?

Could be something related to disk access or RAM, runaway process or 
whatever.
Do you have any system monitoring tools installed? Like munin, atop, 
sysstat?
Any kernel errors in the logs?

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Re: [CentOS] RAID 6 - opinions

[John Doe]

From: Joseph Spenner 

> A RAID5 with a hot spare isn't really the same as a RAID6.  For those not 
> familiar with this, a RAID5 in degraded mode (after it lost a disk) will 
> suffer 
> a performance hit, as well as while it rebuilds from a hot spare.  A RAID6 
> after 
> losing a disk will not suffer.  So, depending on your need for performance, 
> you'll need to decide.
> As far as having a spare disk on a RAID6, I'd say it's not necessary.  
> As long as you have some mechanism in place to inform you if/when a disk 
> fails, 
> you'll not suffer any performance hit.

Also, if you lose a disk, the RAID6 can lose a second disk anytime without 
problem.
The RAID5 cannot until the hot spare has fully replaced the dead disk (which 
can take a while).
And, I believe RAID6 algorithm might be (a little) more demanding/slow than 
RAID5.
Check also RAID50 and 60 if your controller permits it...

JD
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Re: [CentOS] How to determine why a server is not responding

[Dale Dellutri]

On Thu, Apr 11, 2013 at 10:36 AM, nan del bosc  wrote:

> Hi to all!
>
> We're using CentOS 5.5 64bits for our Plesk 11.
>
> This week we had the following problem 3 times...
>
> Suddenly, the server stops responding in all services (SSH, Apache,
> Postfix, ...) but ping works!
>
> After wait a few minutes (or 2 hours some times) the server continues
> unresponsive until we reboot. After reboot we search on /var/log/messages
> but cannot find useful information...
>
...

> What can we do? what can we test?


Are you running  sysstat / sar ?

Perhaps the sa / sar database that's left after reboot can show if some
resource
was over capacity.
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Re: [CentOS] How to determine why a server is not responding

[nan del bosc]

Thank's for your quick answer!

I can't use ipmi in this machine...

# ipmitool sel
Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No
such file or directory
Get SEL Info command failed

# modprobe ipmi_si
FATAL: Error inserting ipmi_si
(/lib/modules/2.6.18-194.26.1.el5xen/kernel/drivers/char/ipmi/ipmi_si.ko):
No such device

# lsmod  |grep ipmi
ipmi_watchdog  52641  0
ipmi_devintf   44753  0
ipmi_msghandler73369  2 ipmi_watchdog,ipmi_devintf

This is a Virtual Server from 1and1, I cannot access the BIOS...

any other idea?


2013/4/11 

> nan del bosc wrote:
> > Hi to all!
> >
> > We're using CentOS 5.5 64bits for our Plesk 11.
> >
> > This week we had the following problem 3 times...
> >
> > Suddenly, the server stops responding in all services (SSH, Apache,
> > Postfix, ...) but ping works!
> >
> > After wait a few minutes (or 2 hours some times) the server continues
> > unresponsive until we reboot. After reboot we search on /var/log/messages
> > but cannot find useful information...
> 
>
> A quick google shows me that the postfix messages are just that, and you
> might want to fix it so it's not asking for it.
>
> HOWEVER, the important thing is that it appears to have just gone
> completely unresponsive. I've seen that happen to some servers here, and
> we've never found any clues On the other hand, IIRC, they tended to be
> boxes that we've had other problems with, and have had a number rebuilt
> under warranty (mostly Penguins, and the problems I've had with them, as
> they're all Supermicro m/b's, told me to NEVER buy a Supermicro m/b).
>
> The only thing I can suggest trying might be to use ipmitool (assuming you
> don't want to bring them down and look in the BIOS) to read the SEL
> (system event log), to look for hardware errors.
>
> mark
>
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>



-- 
---
Salut!
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Re: [CentOS] RAID 6 - opinions

[Joseph Spenner]

>From: "m.r...@5-cent.us" 

>To: CentOS mailing list  
>Sent: Thursday, April 11, 2013 8:36 AM
>Subject: [CentOS] RAID 6 - opinions
 
>
>I'm setting up this huge RAID 6 box. I've always thought of hot spares,
>but I'm reading things that are comparing RAID 5 with a hot spare to RAID
>6, implying that the latter doesn't need one. I *certainly* have enough
>drives to spare in this RAID box: 42 of 'em, so two questions: should I
>assign one or more hot spares, and, if so, how many?

A RAID5 with a hot spare isn't really the same as a RAID6.  For those not 
familiar with this, a RAID5 in degraded mode (after it lost a disk) will suffer 
a performance hit, as well as while it rebuilds from a hot spare.  A RAID6 
after losing a disk will not suffer.  So, depending on your need for 
performance, you'll need to decide.
As far as having a spare disk on a RAID6, I'd say it's not necessary.  As long 
as you have some mechanism in place to inform you if/when a disk fails, you'll 
not suffer any performance hit.
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Re: [CentOS] How to determine why a server is not responding

[m . roth]

nan del bosc wrote:
> Hi to all!
>
> We're using CentOS 5.5 64bits for our Plesk 11.
>
> This week we had the following problem 3 times...
>
> Suddenly, the server stops responding in all services (SSH, Apache,
> Postfix, ...) but ping works!
>
> After wait a few minutes (or 2 hours some times) the server continues
> unresponsive until we reboot. After reboot we search on /var/log/messages
> but cannot find useful information...


A quick google shows me that the postfix messages are just that, and you
might want to fix it so it's not asking for it.

HOWEVER, the important thing is that it appears to have just gone
completely unresponsive. I've seen that happen to some servers here, and
we've never found any clues On the other hand, IIRC, they tended to be
boxes that we've had other problems with, and have had a number rebuilt
under warranty (mostly Penguins, and the problems I've had with them, as
they're all Supermicro m/b's, told me to NEVER buy a Supermicro m/b).

The only thing I can suggest trying might be to use ipmitool (assuming you
don't want to bring them down and look in the BIOS) to read the SEL
(system event log), to look for hardware errors.

mark

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[CentOS] RAID 6 - opinions

[m . roth]

I'm setting up this huge RAID 6 box. I've always thought of hot spares,
but I'm reading things that are comparing RAID 5 with a hot spare to RAID
6, implying that the latter doesn't need one. I *certainly* have enough
drives to spare in this RAID box: 42 of 'em, so two questions: should I
assign one or more hot spares, and, if so, how many?

   mark

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[CentOS] How to determine why a server is not responding

[nan del bosc]

Hi to all!

We're using CentOS 5.5 64bits for our Plesk 11.

This week we had the following problem 3 times...

Suddenly, the server stops responding in all services (SSH, Apache,
Postfix, ...) but ping works!

After wait a few minutes (or 2 hours some times) the server continues
unresponsive until we reboot. After reboot we search on /var/log/messages
but cannot find useful information...

Apr 11 14:56:05 s1 postfix/smtpd[8263]: SQL engine 'intentionally disabled'
not supported
Apr 11 14:56:05 s1 postfix/smtpd[8263]: auxpropfunc error no mechanism
available
Apr 11 14:56:42 s1 postfix/smtpd[8370]: SQL engine 'intentionally disabled'
not supported
Apr 11 14:56:42 s1 postfix/smtpd[8370]: auxpropfunc error no mechanism
available
Apr 11 14:56:47 s1 postfix/smtpd[8391]: SQL engine 'intentionally disabled'
not supported
Apr 11 14:56:47 s1 postfix/smtpd[8391]: auxpropfunc error no mechanism
available
Apr 11 14:56:47 s1 postfix/smtpd[8392]: SQL engine 'intentionally disabled'
not supported
Apr 11 14:56:47 s1 postfix/smtpd[8392]: auxpropfunc error no mechanism
available
Apr 11 16:55:42 s1 syslogd 1.4.1: restart.
Apr 11 16:55:42 s1 kernel: klogd 1.4.1, log source = /proc/kmsg started.
Apr 11 16:55:42 s1 kernel: Bootdata ok (command line is ro root=/dev/xvda1
console=xvc0 console=hvc0 xencons=hvc)
Apr 11 16:55:42 s1 kernel: Linux version 2.6.18-194.26.1.el5xen (
mockbu...@builder10.centos.org) (gcc version 4.1.2 20080704 (Red Hat
4.1.2-48)) #1 SMP Tue Nov 9 13:35:30 EST 2010
Apr 11 16:55:42 s1 kernel: BIOS-provided physical RAM map:
Apr 11 16:55:42 s1 kernel:  Xen:  - 8000
(usable)
Apr 11 16:55:42 s1 kernel: No mptable found.
Apr 11 16:55:42 s1 kernel: Built 1 zonelists.  Total pages: 524288
Apr 11 16:55:42 s1 kernel: Kernel command line: ro root=/dev/xvda1
console=xvc0 console=hvc0 xencons=hvc
Apr 11 16:55:42 s1 kernel: Initializing CPU#0
Apr 11 16:55:42 s1 kernel: PID hash table entries: 4096 (order: 12, 32768
bytes)
Apr 11 16:55:42 s1 kernel: Xen reported: 2009.260 MHz processor.
Apr 11 16:55:42 s1 kernel: Console: colour dummy device 80x25
Apr 11 16:55:42 s1 kernel: Dentry cache hash table entries: 262144 (order:
9, 2097152 bytes)
Apr 11 16:55:42 s1 kernel: Inode-cache hash table entries: 131072 (order:
8, 1048576 bytes)
Apr 11 16:55:42 s1 kernel: Software IO TLB disabled
Apr 11 16:55:42 s1 kernel: Memory: 2043384k/2097152k available (2513k
kernel code, 53108k reserved, 1395k data, 184k init)
Apr 11 16:55:42 s1 kernel: Calibrating delay using timer specific routine..
5025.13 BogoMIPS (lpj=10050261)
Apr 11 16:55:42 s1 kernel: Security Framework v1.0.0 initialized
Apr 11 16:55:42 s1 kernel: SELinux:  Initializing.
Apr 11 16:55:42 s1 kernel: selinux_register_security:  Registering
secondary module capability
Apr 11 16:55:42 s1 kernel: Capability LSM initialized as secondary
Apr 11 16:55:42 s1 kernel: Mount-cache hash table entries: 256
Apr 11 16:55:42 s1 kernel: CPU: L1 I Cache: 64K (64 bytes/line), D cache
64K (64 bytes/line)
Apr 11 16:55:42 s1 kernel: CPU: L2 Cache: 512K (64 bytes/line)
Apr 11 16:55:42 s1 kernel: CPU: Physical Processor ID: 0
Apr 11 16:55:42 s1 kernel: CPU: Processor Core ID: 0
Apr 11 16:55:42 s1 kernel: (SMP-)alternatives turned off
Apr 11 16:55:42 s1 kernel: Brought up 1 CPUs
Apr 11 16:55:42 s1 kernel: checking if image is initramfs... it is
Apr 11 16:55:42 s1 kernel: Grant table initialized
Apr 11 16:55:42 s1 kernel: NET: Registered protocol family 16
Apr 11 16:55:42 s1 kernel: Brought up 1 CPUs
Apr 11 16:55:42 s1 kernel: PCI: setting up Xen PCI frontend stub
Apr 11 16:55:42 s1 kernel: ACPI: Interpreter disabled.
Apr 11 16:55:42 s1 kernel: Linux Plug and Play Support v0.97 (c) Adam Belay
Apr 11 16:55:42 s1 kernel: pnp: PnP ACPI: disabled
Apr 11 16:55:42 s1 kernel: xen_mem: Initialising balloon driver.
Apr 11 16:55:42 s1 kernel: usbcore: registered new driver usbfs
Apr 11 16:55:42 s1 kernel: usbcore: registered new driver hub
Apr 11 16:55:42 s1 kernel: PCI: System does not support PCI
Apr 11 16:55:42 s1 kernel: PCI: System does not support PCI
Apr 11 16:55:42 s1 kernel: NetLabel: Initializing
Apr 11 16:55:42 s1 kernel: NetLabel:  domain hash size = 128
Apr 11 16:55:42 s1 kernel: NetLabel:  protocols = UNLABELED CIPSOv4
Apr 11 16:55:42 s1 kernel: NetLabel:  unlabeled traffic allowed by default
Apr 11 16:55:42 s1 kernel: NET: Registered protocol family 2
Apr 11 16:55:42 s1 kernel: IP route cache hash table entries: 65536 (order:
7, 524288 bytes)
Apr 11 16:55:42 s1 kernel: TCP established hash table entries: 262144
(order: 10, 4194304 bytes)
Apr 11 16:55:42 s1 kernel: TCP bind hash table entries: 65536 (order: 8,
1048576 bytes)
Apr 11 16:55:42 s1 kernel: TCP: Hash tables configured (established 262144
bind 65536)
Apr 11 16:55:42 s1 kernel: TCP reno registered
Apr 11 16:55:42 s1 kernel: audit: initializing netlink socket (disabled)
Apr 11 16:55:42 s1 kernel: type=2000 audit(1365692095.507:1): initialized
Apr 11 16:55:42 s1 kernel: VFS: Disk quotas dquot_6.5.1
Apr 11 16:55

Re: [CentOS] web collaboration packages.

[Jason T. Slack-Moehrle]

Thanks for the notes John, let me go through this process again.




On Thu, Apr 11, 2013 at 3:37 AM, John Doe  wrote:

> From: Jason T. Slack-Moehrle 
> > I can get through the install but Zimbra wont start. It says it started,
> > but didn't I get LDAP errors, Sasl errors, AV and antispam. I worked
> though
> > them a lot yesterday but I still can not get the mta started and nothing
> > starts listening on 443 either. I have Apache not listening to 443, only
> > 80. I turned off the firewall, postfix, sendmail, all just to be sure.
> Both
> > stopping the service and chkconfig so it wont start up again on startup.
> >
> > I was really close yesterday but I gave up again. I even tried 7.2.3
> > instead of 8.0.3 and that seemed worse. I uninstalled everything and
> > removed all the pieces and figured that I would give it a shot again
> today.
>
> Nothing in the zimbra logs?
>
> I started with a 6.x.x on CentOS 5, and I upgraded it up to 7.2.0.
> So it is not the same setup as yours...
> >From my notes, I did:
>   yum install nc libidn-devel gmp-devel perl-Net-Ident perl-Razor-Agent \
>   perl-Encode-Detect
>   ./install.sh --platform-override
>   Change domain name? [Yes]
>   Create domain: [] 
>   3) zimbra-store:
> Server mode: mixed
>   cd /usr/sbin
>   mv sendmail sendmail.old; ln -s /opt/zimbra/postfix/sbin/sendmail
> sendmail
>   Copy ssl keys to /opt/zimbra/ssl/zimbra/commercial/
> commercial.key
> commercial.crt
> commercial_ca.crt
>   /opt/zimbra/bin/zmcertmgr verifycrt comm commercial.key commercial.crt
>   /opt/zimbra/bin/zmcertmgr deploycrt comm commercial.crt commercial_ca.crt
>   Change ports:
> zmprov -l gs  | grep "Port:"
> zmprov -l ms  zimbraMailPort 80 zimbraMailProxyPort 0 \
>  zimbraMailSSLPort 443
> zimbraMailSSLProxyPort 0
> zmprov -l gs  | grep "Port:"
> zmcontrol restart
>
> JD
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Re: [CentOS] floppy drives

[m . roth]

Denniston, Todd A CIV NAVSURFWARCENDIV Crane wrote:
>> From: m.r...@5-cent.us [mailto:m.r...@5-cent.us]
>> Frank Cox wrote:
>> > On Tue, 9 Apr 2013 10:19:33 -0400
>> > m.r...@5-cent.us wrote:
>> >
>> >> Hmmm... didn't see it mounted, but I'll try more tonight. Last night
>> >> included a) playing with system, and b) finishing up our federal
>> >> taxes

>> I also can't seem to find the USB 3.5" drive I borrowed - lsusb sees it
>> (at least since the last reboot), but trying to find it to mount it is
>> something I'm still digging at, and I doubt mtools can find it.
>
> Note: the USB floppy may be showing up as /dev/sd[bcd...n]
> At least that is what happened when I used one on RHEL/CentOS5 a while
> back.

I would think, but don't remember seeing it.
>
> I suggest unplugging the USB floppy, execute `ls /dev/sd* /dev/fd*`,
> plug it in and execute `ls /dev/sd* /dev/fd*`, and then note the
> differences.

Think I tried that, as well as leaving the USB drive in when I bounced the
system to reset the BIOS. USB storage annoys me, half the time it's try to
find it, the camera card being a prime example. I'll try it this evening,
since we *finally* finished all the taxes last night (MD is nasty: their
downloadable pdf forms are encrypted, so not only is it not saveable after
you enter data, like the fed forms are, but you cannot use either print to
CUPS-pdf, nor can you print to a file, then use ps2pdf)
>
> {there are probably hal/udev/inotify games you could do, but I like old
> fashioned things.}

Hmmm, don't know them. rescan-scsi-bus... no, I don't *think* that will
register the USB, and I think I mentioned that lsusb shows me the drive,
but I can't identify the driver. Now that I have some time, I'll dig
deeper.

>
> Even when this disclaimer is not here:
> I am not a contracting officer. I do not have authority to make or modify
> the terms of any contract.

I have a very long disclaimer from my late wife at home, along the lines
of "this does not reflect the views of my employer, the US government, or
even the view out my window (which I don't have)"

mark

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Re: [CentOS] floppy drives

[Denniston, Todd A CIV NAVSURFWARCENDIV Crane]

> -Original Message-
> From: m.r...@5-cent.us [mailto:m.r...@5-cent.us]
> Sent: Tuesday, April 09, 2013 12:21
> To: CentOS mailing list
> Subject: Re: [CentOS] floppy drives
> 
> Frank Cox wrote:
> > On Tue, 9 Apr 2013 10:19:33 -0400
> > m.r...@5-cent.us wrote:
> >
> >> Hmmm... didn't see it mounted, but I'll try more tonight. Last night
> >> included a) playing with system, and b) finishing up our federal
> >> taxes
> >
> > If you're going to use mtools to do your copying, you don't need to
> mount
> > the disks.
> 
> mtools is a desperation move, since I haven't actually read anything
> from
> anything yet. As I mentioned, I *may* have an old drive head cleaner
> somewhere - since it's not been used in about a decade, I'm thinking of
> corrosion or crud.
> 
> I also can't seem to find the USB 3.5" drive I borrowed - lsusb sees it
> (at least since the last reboot), but trying to find it to mount it is
> something I'm still digging at, and I doubt mtools can find it.
> 
>  mark
> 

Note: the USB floppy may be showing up as /dev/sd[bcd...n]
At least that is what happened when I used one on RHEL/CentOS5 a while back.

I suggest unplugging the USB floppy, execute `ls /dev/sd* /dev/fd*`, 
plug it in and execute `ls /dev/sd* /dev/fd*`, and then note the differences.

{there are probably hal/udev/inotify games you could do, but I like old 
fashioned things.}

Even when this disclaimer is not here:
I am not a contracting officer. I do not have authority to make or modify the 
terms of any contract.


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[CentOS] CentOS-announce Digest, Vol 98, Issue 5

[centos-announce-request]

Send CentOS-announce mailing list submissions to
centos-annou...@centos.org

To subscribe or unsubscribe via the World Wide Web, visit
http://lists.centos.org/mailman/listinfo/centos-announce
or, via email, send a message with subject or body 'help' to
centos-announce-requ...@centos.org

You can reach the person managing the list at
centos-announce-ow...@centos.org

When replying, please edit your Subject line so it is more specific
than "Re: Contents of CentOS-announce digest..."


Today's Topics:

   1. CEBA-2013:0732  CentOS 5 glibc Update (Johnny Hughes)
   2. CEBA-2013:0734  CentOS 5 esc Update (Johnny Hughes)
   3. CEBA-2013:0735  CentOS 6 esc Update (Johnny Hughes)


--

Message: 1
Date: Wed, 10 Apr 2013 19:28:49 +
From: Johnny Hughes 
Subject: [CentOS-announce] CEBA-2013:0732  CentOS 5 glibc Update
To: centos-annou...@centos.org
Message-ID: <20130410192849.ga25...@chakra.karan.org>
Content-Type: text/plain; charset=us-ascii


CentOS Errata and Bugfix Advisory 2013:0732 

Upstream details at : https://rhn.redhat.com/errata/RHBA-2013-0732.html

The following updated files have been uploaded and are currently 
syncing to the mirrors: ( sha256sum Filename ) 

i386:
4db7f0ddb292c08ee3e380209cdd8308136d6ce30f552b63290e92b80a540a5a  
glibc-2.5-107.el5_9.1.i386.rpm
9067102b8ac1825ee50ef6fba732507429e8cea968b2747a868fe09da5ac4e2b  
glibc-2.5-107.el5_9.1.i686.rpm
ca59b16a43aa5244fdcb44b14a928101d76d01230f8d614129c4da80cb8990df  
glibc-common-2.5-107.el5_9.1.i386.rpm
40d8e708341a0ecb2436cbb6b914261726b5377635e6cada32619fc3b74ef30d  
glibc-devel-2.5-107.el5_9.1.i386.rpm
3060f66eba6a6cea01f0ee24e1b96376062c740c7ec4f368374a6e48924724a9  
glibc-headers-2.5-107.el5_9.1.i386.rpm
80ecdd22857d2fb9414852cf0efc93314324ee3e51d77d06e7100c7e7699e04e  
glibc-utils-2.5-107.el5_9.1.i386.rpm
acf033dfb507f86cfc8fd090ae4fe0e9a22088dfb920b0ec68a75f8c1e1923cf  
nscd-2.5-107.el5_9.1.i386.rpm

x86_64:
9067102b8ac1825ee50ef6fba732507429e8cea968b2747a868fe09da5ac4e2b  
glibc-2.5-107.el5_9.1.i686.rpm
662d1fceee8c2b4cb68304b778ba8900f71003769b79fb02b0be9ae918570be3  
glibc-2.5-107.el5_9.1.x86_64.rpm
f35415a4b902a00ec86e3645a35ac1a8b067c8a51c7a6db90fc2afe840826a83  
glibc-common-2.5-107.el5_9.1.x86_64.rpm
40d8e708341a0ecb2436cbb6b914261726b5377635e6cada32619fc3b74ef30d  
glibc-devel-2.5-107.el5_9.1.i386.rpm
5d63400d62a4e5c8994d1d9a773119154790931223f081221337f9766257f293  
glibc-devel-2.5-107.el5_9.1.x86_64.rpm
db23fd79c60e6e3f90acb0319f216a2135fb0c5e25d19b98c77a84590e5669e7  
glibc-headers-2.5-107.el5_9.1.x86_64.rpm
ce0bf37712e3b486c635a3ead465326bdc02335c3a31804a794f687372a6073c  
glibc-utils-2.5-107.el5_9.1.x86_64.rpm
0001647c0dfb7825d2a1ecc32e37c4b10249208b8ed6cdcd77b6612297166009  
nscd-2.5-107.el5_9.1.x86_64.rpm

Source:
c7a9bf801cafabcd527bd7619f8389333e9a909c53b9f9bc10fde19ca3e127df  
glibc-2.5-107.el5_9.1.src.rpm



-- 
Johnny Hughes
CentOS Project { http://www.centos.org/ }
irc: hughesjr, #cen...@irc.freenode.net



--

Message: 2
Date: Wed, 10 Apr 2013 21:23:59 +
From: Johnny Hughes 
Subject: [CentOS-announce] CEBA-2013:0734  CentOS 5 esc Update
To: centos-annou...@centos.org
Message-ID: <20130410212359.ga31...@chakra.karan.org>
Content-Type: text/plain; charset=us-ascii


CentOS Errata and Bugfix Advisory 2013:0734 

Upstream details at : https://rhn.redhat.com/errata/RHBA-2013-0734.html

The following updated files have been uploaded and are currently 
syncing to the mirrors: ( sha256sum Filename ) 

i386:
1dd83700f6d7dc2c5457475d26810d9c2b03fc828fd01736475170bc24487eb8  
esc-1.1.0-14.el5.centos.1.i386.rpm

x86_64:
5fb2cd5de0c08fafd15b1992a254e7bb357dc8b02537991cc19f1f2bf1d06eb7  
esc-1.1.0-14.el5.centos.1.x86_64.rpm

Source:
9487b089d041c395c57dddb0f75142a6249fffe261aea722a7e231a946775619  
esc-1.1.0-14.el5.centos.1.src.rpm



-- 
Johnny Hughes
CentOS Project { http://www.centos.org/ }
irc: hughesjr, #cen...@irc.freenode.net



--

Message: 3
Date: Wed, 10 Apr 2013 22:47:32 +
From: Johnny Hughes 
Subject: [CentOS-announce] CEBA-2013:0735  CentOS 6 esc Update
To: centos-annou...@centos.org
Message-ID: <20130410224732.ga4...@chakra.karan.org>
Content-Type: text/plain; charset=us-ascii


CentOS Errata and Bugfix Advisory 2013:0735 

Upstream details at : https://rhn.redhat.com/errata/RHBA-2013-0735.html

The following updated files have been uploaded and are currently 
syncing to the mirrors: ( sha256sum Filename ) 

i386:
02774e31c54e68add6b8a0963b4aa3060fb488087da30c400c84bf6a8f339fe2  
esc-1.1.0-25.el6.centos.1.i686.rpm

x86_64:
d56acd10070481335614b5a1bb413f0cf87e2bc62ea0186cb420478644a678e1  
esc-1.1.0-25.el6.centos.1.x86_64.rpm

Source:
0ca79f8310cdf46508327e3542a284a081b4bbe0167e01950232896c668a59df  
esc-1.1.0-25.el6.centos.1.src.rpm



-- 
Johnny Hughes
CentOS Project { http://www.centos.org/ }
irc: hughesjr, #cen...@irc.freenode.net



---

Re: [CentOS] web collaboration packages.

[John Doe]

From: Jason T. Slack-Moehrle 
> I can get through the install but Zimbra wont start. It says it started,
> but didn't I get LDAP errors, Sasl errors, AV and antispam. I worked though
> them a lot yesterday but I still can not get the mta started and nothing
> starts listening on 443 either. I have Apache not listening to 443, only
> 80. I turned off the firewall, postfix, sendmail, all just to be sure. Both
> stopping the service and chkconfig so it wont start up again on startup.
>
> I was really close yesterday but I gave up again. I even tried 7.2.3
> instead of 8.0.3 and that seemed worse. I uninstalled everything and
> removed all the pieces and figured that I would give it a shot again today.

Nothing in the zimbra logs?

I started with a 6.x.x on CentOS 5, and I upgraded it up to 7.2.0.
So it is not the same setup as yours...
>From my notes, I did:
  yum install nc libidn-devel gmp-devel perl-Net-Ident perl-Razor-Agent \
  perl-Encode-Detect
  ./install.sh --platform-override
  Change domain name? [Yes]
  Create domain: [] 
  3) zimbra-store:
    Server mode: mixed
  cd /usr/sbin
  mv sendmail sendmail.old; ln -s /opt/zimbra/postfix/sbin/sendmail sendmail
  Copy ssl keys to /opt/zimbra/ssl/zimbra/commercial/
    commercial.key
    commercial.crt
    commercial_ca.crt
  /opt/zimbra/bin/zmcertmgr verifycrt comm commercial.key commercial.crt
  /opt/zimbra/bin/zmcertmgr deploycrt comm commercial.crt commercial_ca.crt
  Change ports:
    zmprov -l gs  | grep "Port:"
    zmprov -l ms  zimbraMailPort 80 zimbraMailProxyPort 0 \
 zimbraMailSSLPort 443 zimbraMailSSLProxyPort 0
    zmprov -l gs  | grep "Port:"
    zmcontrol restart

JD
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Re: [CentOS] Cluster SW

[Woehrle Hartmut SBB CFF FFS (Extern)]

> Hi,
> How to download  Cluster SW and how to configure clustering in CentOS.
>With Regards and  good wishes.
>
>V.SANTOSH

What do you want to cluster (disks, services, data,...)
How (failover, loadbalancing, master-slave,...)

Hartmut


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Re: [CentOS] Formatting a USB Drive

[John Doe]

From: Jason T. Slack-Moehrle 
> So I run:
> # parted
> GNU Parted 2.1
> Using /dev/sda
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) select /dev/sdg
> Using /dev/sdg
> (parted) print
> Model: DROBO DroboPro (scsi)
> Disk /dev/sdg: 17.6TB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number  Start  End  Size  File system  Name  Flags
>
> (parted)
>
> and looking at an example of creating a partition: (parted) mkpart primary
> 106 16179
>
> I dont know what to do next since I dont see any partitions listed. I dont
> know what do to for the start and end point, although the man page says
> "size in MB". Do I just say 0 to (and convert 16.0TB to MB? Yes, I
> know it
> says 17.6 TB but this model drobo can only support partitions up to 16tb
> without making a second partition.
>
> Can anyone provide some advice on that I am missing conceptually?

When I had to play with GPT for a 3TB disk, I did:
  gdisk -l /dev/sdc
  parted -s /dev/sdc mklabel gpt
  parted -s -a optimal /dev/sdc unit s mkpart primary ext4 2048 

Not sure if optimal, but it worked...

JD
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[CentOS] centos 6.3 ipv6 default gateway

[Jaze Lee]

hello,
   i met a problem in configuratiion of ipv6 gw in my box
i install centos 6.3 (64 bit) on my boxs, which have four netcard.
i use a straight-through cable to connect centosv0:netcard-2 and
centosv1:netcard2
the topology is this:
client c(windows xp) <-->centosv0:netcard-3 <--> centosv0:netcard-2 <--->
centosv1:netcard-2 <>centosv1:netcard-2  <---> client d (backtrack r2
32)
1:2:3:4::2/64  1:2:3:4::1/64   1:2:3::4/64
  1:2:3::5/64 1:2:3:5::1/64
 1:2:3:5::2/64

what i want to do is set default gw on centosv0 to centosv1

i configure /etc/sysconfig/network-scripts/ifconfig-eth2  (centosv0) as this
DEVICE="eth2"
BOOTPROTO=static
HWADDR="60:A4:4C:23:2F:6F"
NM_CONTROLLED="yes"
ONBOOT="yes"
TYPE="Ethernet"
#UUID="0ddcf499-878f-4ac7-9d1a-c27f85d2bccf"
IPV6INIT=yes
IPV6ADDR=1:2:3::4
IPV6_DEFAULTGW=1:2:3::5

and i also configure /etc/sysconfig/network to this:
NETWORKING=yes
HOSTNAME=centosv0
NETWORKING_IPV6=yes
IPV6_AUTOCONF=no

but i met an error:
Bringing up interface eth2:  WARN : [ipv6_add_route] Unknown error

i do not know how why,and can some one gives me some suggestion?
thanks a lot.
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[CentOS] Cluster SW

[santosh venkataswamy]

 Hi,
 How to download  Cluster SW and how to configure clustering in CentOS.
With Regards and  good wishes.

V.SANTOSH
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Re: [CentOS] NFS client caching

[James Pearson]

Bazy [baz...@gmail.com] wrote:
>
> I've just read how GoDaddy upgraded its servers to CentOS6 and in the
> article they wrote about "NFS client caching".
> Can anyone point me to documentation they used to implement NFS client
> caching? Tips and tricks are welcome :-)

I guess they are using FS-Cache - see:



and:



I haven't used it in production, so have no idea how good (or bad?) it is - 
however, I suggest you read the 'Performance Guarantee' in the first link above 
...

James Pearson
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[CentOS] NFS client caching

[Bazy]

Hello,

I've just read how GoDaddy upgraded its servers to CentOS6 and in the 
article they wrote about "NFS client caching".
Can anyone point me to documentation they used to implement NFS client 
caching? Tips and tricks are welcome :-)

Cheers!

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