CentOS - Mar 2007 - Hellllp Pl: Centos 4.4 Default LVM install boot/recovery problem

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.

Sanjay Arora spake the following on 3/17/2007 12:24 PM:
> 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.


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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.

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,

Theo