Live CD for RAID recover?

Facepalm41 · 11-10-2011, 05:10 PM

Hey, I recently broke my Debian kernel. I'm missing libraries. However, to put these libraries back where they belong I need some sort of a live CD or some guidance from a pro. Does such a thing exist?

--I have tried Ubuntu 10.04 LTS 32-bit, Knoppix 6.7 and GParted Live. The most success I have had is with Knoppix, I get three drives that are not right (with mdadm --configure --scan) and they are /dev/md126, /dev/md127 and /dev/md128. Note that /dev/md127 is the boot directory housing /grub and the kernel only.

Do I have hope?
Thank you.

--EDIT--
Raid card is an Adaptec SCSI RAID adapter 39160
Motherboard: TYAN S4882 Thunder K8
CPU: 4 Opteron 850s
RAM: 8GB Kingston HyperX DDR ECC
Drives: 8 SCSI drives, assorted make and model, 73GB each

jefro · 11-10-2011, 07:58 PM

If you had debian then I'd have started with the debian live cd and recreate or try to fix the array.
Or find a debian live more similar than current stable that is equal to your originally working version.

http://live.debian.net/

http://cdimage.debian.org/cdimage/release/current-live/

jlinkels · 11-10-2011, 08:27 PM

If you have a recent Debian installation, you can download the live-USB stick with the same version and kernel as your current installation.

Boot with the USB, your RAID will assemble (1). Mount the directory tree under the mount point on the USB stick. If you have multiple partitions, mount / first, then the other directories below /.

Excecute chroot into the / of the RAID (where you mounted it on the USB stick). If that was succesful, take it from there and re-install your things.

A cdrom is likely to work as well, but USB is more 2011-like.

(1): I know this sounds almost unbelievable, but it does assemble the RAID although your USB sticks doesn't know anything about that you intend to use a RAID. In case it is not assembling, use the mdadm tools to assemble it. I forgot the commands, but you can have mdadm discover and rebuild etc. Don't try to mount a single disk (unRAIDED) though as that will ruin the array when you write on it.

jlinkels

Edit: you'll need the rescue version in order to have mdadm included.

Facepalm41 · 11-21-2011, 02:01 AM

Okay, sorry for long time no reply! I've got the same Debian live CD as the original OS and I've also got the same kernel. However, it does not want to assemble the RAID array. It says that my RAID5 array is RAID1 and gives the following error:

Code:

md: md0 stopped.
md: bind<sdb1>
md: sdc1 has same UUID but different superblock to sdb1
md: sdc1 has different UUID to /dev/sdb1
md: export_rdev(sdc1)
mdadm: failed to add /dev/sdc1 to /dev/md0: Invalid argument

I get this same error for all of these drives (all in the array):
/dev/sdc1
/dev/sdd1
/dev/sdf1
/dev/sdg1
/dev/sdh1

jefro · 11-21-2011, 03:46 PM

Is the data all there?

Facepalm41 · 11-21-2011, 04:13 PM

As far as I know, everything is still there. Using another Live CD I was able to start the array off of one disk and get to the /bin/boot and that's it. That's where I got the kernel.

jefro · 11-21-2011, 05:26 PM

Then I'd copy it off and then diag this more.

Facepalm41 · 11-21-2011, 05:53 PM

I would do that, but there's the problem - I can't get to the data. I can only get the kernel and the boot directory, and I have that already. The rest of the stuff is on the RAID array that won't mount.

jefro · 11-21-2011, 08:32 PM

Darn, is this a real hardware raid actually?

Facepalm41 · 11-22-2011, 03:00 PM

Probably not, because the RAID controller is not that fancy. There are no options in its BIOS for setting up RAID, besides when kernels look at it they see all of the individual drives and don't bother with the "Linux_raid_autodetect" partitions.

Facepalm41 · 11-22-2011, 03:23 PM

Wild idea: Would it be possible to rebuild my kernel so that it looks for the missing libs on a CD, while booting from the RAID array? My kernel is vmlinuz-2.6.26.2-amd64. If I can do that, then I get a rudimentary OS that actually loads the array, and I can copy the libs and the old kernel over.

jefro · 11-22-2011, 08:31 PM

Might wish to post that as a single question on a new post. I think you could link any file to suite.

My question is how did you get this thing working originally. If you just put in a cd and when then the live cd ought to recover it enough to see the files. Why can't we just access the array?

I looked that up. It should be a real hardware array adapter. Did you create the array with the scsi bios and utilities? I never heard of a software array from adaptec. Also it is possible you didn't use it to create the array, that would not have made sense.

Facepalm41 · 11-22-2011, 08:54 PM

A friend of mine set it up with mdadm on a Debian server distro a few years back on the then-new Aberdeen server.

Anyways, onto your idea, the problem I have now is that I don't seem to be able to see the rest of the array. When I used my Knoppix CD and followed the mdadm MAN file, I was only able to get one drive going - the boot 'array'. That had the kernel and grub, that's it. Problem is, I know where the superblocks are, but I don't know the drive configuration. How would I go about finding it out?