Re: [Xen-users] Re: domU corrupt after server crash, help needed trying to recover domU

[Rudi Ahlers <rudiahlers@xxxxxxxxx>]

On Sun, May 10, 2009 at 9:38 AM, Rudi Ahlers <rudiahlers@xxxxxxxxx> wrote:

On Sat, May 9, 2009 at 5:19 AM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote:

On Sat, May 9, 2009 at 5:42 AM, Rudi Ahlers <rudiahlers@xxxxxxxxx> wrote:
> Hi Fajar,
>
> I got the commands via google search, so I didn't know that losetup was only
> meant for file-backed storage.

If it's a block device (LVM, partition, etc.) you can skip losetup and
go directly to
kpartx -av  /dev/data/hfserver2

Really? Cool, now I've learned something :)
 

> Unfortunately there's no backups :(

Ouch. Sorry to hear that.
So that makes it what ... your second corruption?
On my environment FS corruption is USUALLY because one of these :
- human error (like the admin mounting the same block device twice on
different servers). This usually happens on shared-storage systems
(SAN, NAS, etc).
- SAN error (like when it got temporarily disconnected, and then
reconnected again)
- server hardware error (bad memory, bad disk controller, etc.)

Yes, but on a different server, different client, different reason. The only thing that's the same is the IDC, and the server setup. Both have CentOS on the host node, and runs cPanel on the domU VPS's. I'd love to setup a shared NAS and have 2 servers shared the data from there, but funds are a bit limited :(
 

I suggest you check all three to make sure corruption doesn't happen
again. If both corruption are on the same hardware, then most likely
the server hardware is bad.

The problem is due to the RAM. The ECC (non buffered) Kingston Memory modules don't work as expected on the Dell PE860 platform. Strangely when I put normal desktop RAM into the server, it worked fine. So, I'm taking the RAM back to the supplier on Monday.

You could PROBABLY still salvage some data from the broken domU. Try
shutting it down, and mount it again on dom0. Sometimes fsck will find
recovered inodes in /lost+found, so perhaps some of your data is still
there.

Yes, I'm going to try this and see how far I can get.
 

BTW, VolGroup00 IS the name of domU's VG right? It's not dom0's VG?
Cause if it were dom0's you might have more problems ahead.

no, the hostnode's LVM has been renamed to /dev/data/root, /dev/home/swap & /dev/data/home for this very reason
 

Regards,

Fajar

Just as matter of interest, the amount of recovered files in /mnt/cpanel/lost+found/ (this is the mounted VolGroup00 partition) is 32536

And the files all looks like this:

-rw-r----- 1 root       32046   94816 Feb 12 10:28 #1865704
-rw-r--r-- 1 root     root         91 Feb 12 10:28 #1865705
-rw-r----- 1 root       32052   94816 Feb 12 10:28 #1865707
-rw-r----- 1 root       32022     901 Feb 12 10:28 #1865709
-rw-r----- 1 root       32052   94816 Feb 12 10:28 #1865710
-rw-r----- 1 root       32013   94816 Feb 12 10:28 #1865711
-rw-r----- 1 root       32013   94816 Feb 12 10:28 #1865713
-rw-r--r-- 1 root     root         91 Feb 12 10:28 #1865714
-rw-r----- 1 root       32037   94816 Feb 12 10:28 #1865715
-rw-r----- 1 root         506   94816 Feb 12 10:44 #1865716
-rw-r----- 1 root       32037    6202 Feb 12 10:28 #1865717
-rw-r--r-- 1 root     root         92 Feb 12 10:44 #1865718
-rw-r--r-- 1 root     root        105 Feb 12 10:44 #1865719
-rw-r----- 1 root       32029   94816 Feb 12 10:44 #1865721
-rw-r----- 1 root       32029   94816 Feb 12 10:44 #1865722
-rw-r----- 1 root       32029   94816 Feb 12 10:44 #1865723
-rw-r-0m#1865794
-rw-r----- 1 root       32029   94816 Feb 12 16:47 #1865795
[root@xen cpanel]# ll lost+found/ | wc -l



What can I do with these files, apart from deleting them?

-- 
Kind Regards
Rudi Ahlers
CEO, SoftDux Hosting
Web: http://www.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532
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