root restore onto a logical volume

"David Spear" <dspear@telus.net> · Mon, 31 May 2004 11:23:00 -0700

Heinz:

I’ve posted to various newsgroups, combed through FAQ’s,
and can’t find an answer to my problem.  

I have my root “/” on a logical volume
/dev/Volume00/RootVol, which is in turn mounted on a software RAID-5 volume,
/dev/md1.  I wanted to test my crash
recovery, i.e. see if my backups were working.  So rather than test it on my working
system, I decided to create a new logical volume, /dev/Volume00/TestRoot.  I did the following:

 Boot
     from cd to shell
 Manually
     start my raid volumes via raidstart
 Manually
     activate my logical volumes via pvscan, vgscan, lvscan, lvchange.
 Create
     a new logical volume, /dev/Volume00/TempRoot.
 Mount
     /dev/Volume00/TempRoot
 Restore
     from tape to TempRoot
 Change /tmp/TempRoot/etc/fstab to reflect new root location “/dev/Volume00/TempRoot”
     instead of /dev/Volume00/RootVol
 Create
     a test entry in /tmp/TempRoot/etc/lilo.conf with
     the new root location “/dev/Volume00/TempRoot” and run lilo.
 Reboot

When my kernel gets to the point where it need to access “/”
I get an error, “cannot mount /dev/Volume00/TempRoot, bad superblock, try e2fsck –b 8193, etc. etc. etc.”.  When it
dumps me to a shell and I run “vgscan” I get “no volumes found” yet,
when I run “pvscan” it lists one volume
found “Volume00” on /dev/md1.

Did I miss something in my restore?  Do I need to restore a configuration of
some sort?  I have read through the manpages on vgcfgbackup and vgcfgrestore and believe that these write out
configurations to the physical volumes. 
As I can boot my old root (or boot from cd)
and both see and mount /dev/Volume00/TempVol I’m sure there’s
nothing wrong with my volume group configuration on the disks…

Sorry to ask such a question, but as I said I’ve
looked and looked and looked for answers elsewhere to no avail.

Any answer greatly appreciated.

Thanks

Dave

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