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

Wed Mar 21 22:38:44 UTC 2007
Scott Silva <ssilva at sgvwater.com>

Sanjay Arora spake the following on 3/21/2007 12:38 PM:
> On Wed, 2007-03-21 at 08:42 +0530, 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.
>>
>> If LVM volume was spread across all the drives, and one drive is damaged, you
>> will have a hard time recovering the data. It can be done, but it will be
>> difficult. Do you have a better idea of how the data was laid out?
>> If there was electrical problems, you might have damage to this system also.
>>
> I don't think there is any physical damage to these HDDs, as the system
> boots & acceses the boot partition & gets CRC error on reading some
> data...maybe lvm data.
> 
> And yes, the lvm volume would be spread across all the HDDs. So how do I
> find out lvm configuration data and give it to lvm? or maybe there is a
> way to mount lvm slices one by one and copy the data to a fourth HDD?
> 
> With regards & thanks for taking the time to respond.
> 
> Sanjay.
Have you tried to boot from the CentOS live CD?
It has some rescue tools, and might be able to find your LV's.

The LVM howto has some basic ideas, but be careful if your data is
irreplaceable. If it is critical data, you might want to call a recovery
service. Mucking around with it might just make the data go bye bye forever.

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