I had a CentOS 5 installation that went belly up, yesterday. After an extensive fsck, I had a system that I could boot but couldn't log in to.

So I've built a new CentOS 5 installation, on a new HD, and now I'd like to mount my old HD< so I can copy files from it.

Problem is CentOS 5 uses these new LVM logical volumes, that I don't really understand.

It looks like during the boot process the LVM system recognized that it had two sets of logical volumes on disk, with identical names, and chose the one on the boot disk to mount.

So what I have is /dev/hda1 as boot, and /dev/hda2 as VolGroup00.

And /dev/hdb1 as boot, and /dev/grb2 as VolGroup00.

In any case, mount shows / mounted on /dev/mapper/VolGroup00-LogVol00.
It looks like /dev/mapper/VolGroup00-LogVol01 is configured as swap.

vgscan shows VolGroup00 twice.

lvscan shows /dev/VolGroup00/LogVol00 and /dev/VolGroup00/LogVol01.

In other words, only two of the logical volumes show up, I'm assuming because the volume groups have the same name.

How do I mount the second Volgroup00/LogVol11?

You change it's name - this comes up all the time on the Redhat/Fedora fora.
Search on vgrename.

How do I specify which of the two VolGroup00 is the one I want to rename?

I take the drive I don't want to change out of the box, and boot from the rescue CD. Doh!

Repeating what I found in another thread, for anyone who follows along:

Two LVM VolGroup's, same name, one is system disk - what to do?

From the rescue CD:

# this scans for and activates the logical volumes:
lvm vgscan
lvm lvscan
lvm vgchange -a y
lvm pvscan
lvm lvscan

# this deactivates the logical volumes so we can change the name of the volume group:
lvm vgchange -a n

#this changes the name of the volume group:
lvm vgrename VolGroup00 VolGroup01

Shut down, put the other drive in, and boot from the new drive.

#create a mount point for the old drive
mkdir /mnt/old/root

#mount the old drive
mount -t ext3 /dev/mapper/VolGroup01-LogVol00 /mnt/old/root

Thanks, folks, for the help.