[CentOS] Hellllp Pl: Centos 4.4 Default LVM install boot/recovery problem

Wed Mar 21 22:55:58 UTC 2007
Theo Band <theo.band at xanadu-wireless.com>

Sanjay Arora wrote:
> Hello all
> Nill experience with LVM. Have a Default Centos 4.4 install updated till
> a week ago with three HDDs. System's not booting up since my staff
> pulled out the plug due to a short circuit nearby. 
> Machine is a PIII 550 MHz, with 3 HDDs 40 GB, 120 GB (Actually is bigger
> but my bios detects only upto 120 GB) & 20 GB...about half filled with
> data & the backup server taken out in the short circuit.
> Upon bootup, the system starts with root, kernel & initrd notices, then
> says Uncompressing Linux then spits out the Error....CRC Error -- System
> Halted.
> Booted from the CD in reinstall mode where anaconda looks for linux
> installations on the HDD and asks about upgrade, reinstall or fresh
> partition/create partition/delete partition for reinstall, but the
> installer does not detect any linux installation on the HDD. I aborted
> at that stage.
> Now my system is a default linux installation where I have used the
> autopartitioning done by the system (LVM2) and almost all of my data is
> either in /home directory or couple of directories in the /
> I am willing to do a reinstall if my data is preserved. What do I need
> to do to diagnose the problem? and pointers to recovering from this
> problem and various tradeoffs. Can't lose data, as already have lost
> backup server (smps, motherboard, hdd circuitry all short-circuited, so
> no hope there). LVM howto was not much of a help as it seems to mostly
> have how to expand or reduce lvm and similar issues.
> Please keep in mind that I am a user and not sys-admin, though I can use
> command-line, if instructions & how-tos are there.
> Please help.
> With best regards and thanks in anticipation.
> Sanjay.

The steps I would try are:

* boot in rescue mode (linux rescue)
* use lvscan to try to find LVM groups
* Then activate the volume group by
  vgchange -a y

You can see for yourself were things start to fail.

Good luck,