I'm running CentOS 5.5.

A couple of weeks ago, my 500 GB disk crashed after suffering an accelerating error rate for a couple of days.

Now that I have a new disk in place, I want to mount my old disk,
which is (was) an LVM disk, as a second disk and recover files
from it if possible.

The question is, how do I go about this?

If I mount the old disk:

# mount /dev/sdb1 /sdb1

the top-level directory shows only two subdirectories:

lost+found, which is empty;
restored, which is an image of files recovered from old disk's predecessor.

'df' shows (or appears to show) that the disk is 11% full.
Sorry, I don't recall how full the disk was before it crashed.

How do I get the system to recognize the LVM structure on the old disk & mount it?

Or is the directory structure too corrupted? Do I need to send the disk out to a recovery service?

-- Thanks!

P.S. Have aleady done some poking around with lvmdiskscan, which shows the old disk whether it's mounted or not, and vgchange -ay, which doesn't appear to do anything.

If /dev/sdb is your old disk and you were were able to mount sdb1, something is wrong and that partition is no longer an LVM Physical volume.

If it is an LVM PV, a mount of it would give you message something like "mount: unknown filesystem type 'lvm2pv'". And in that case, when you are looking at /sdb1 you are looking at data in that mountpoint directory not in the mounted filesystem.

What you really need to be doing is mounting the LVM Logical Volumes that are in the Volume Group on that Physical Volume. Something like 'mount /dev/<VG>/<LV> /<somemountpoint>' or 'mount /dev/mapper/<VG>-<LV> /<somemountpoint>'. Be aware that activating that VG may be a problem if the VG name on the old disk is the same as a VG name that is already active on your system. (There are ways around it, ie. changing the VG name on the old disk before you activate it.)

Please supply the output of your 'lvmdiskscan', a 'pvscan', and a 'vgchange -ay -vv'. And the output from 'mount' and 'df' would be helpful as well.