[CentOS] Making a clone of an LVM-based EL5 install

Tue Mar 19 12:10:46 UTC 2013
Mike Burger <mburger at bubbanfriends.org>

Mondo?

http://www.mondorescue.org
-- 
Mike Burger
http://www.bubbanfriends.org

"It's always suicide-mission this, save-the-planet that. No one ever just
stops by to say 'hi' anymore." --Colonel Jack O'Neill, SG1


> Does anybody here have any idea how to make an exact copy of a drive
> that has LVM partitions? I'm having trouble using dd to do this for an
> EL5 server.
>
> We're trying to diagnose a software problem of some kind and would like
> an exact, perfect copy of the software running so that we can see
> exactly what the problem is without disturbing our production copy. It's
> been admin practice to set up a single server with the ideal image as
> desired, and then use DD to replicate that image to multiple hosts.
> We've done this a large number of times. The exact procedure followed is:
>
> -) Perform typical file-level backups with rsync
> -) Install additional HDD (hereafter sdb) as least a big as the HDD to
> be duplicated.
> -) Boot off a CentOS install DVD with "linux rescue"
> -) Where /dev/sda is the original drive and /dev/sdb is the new drive,
> run:
>      dd bs=8192 if=/dev/sda of=/dev/sdb;
> -) shutdown the server upon completion of the previous command and
> remove 2nd drive.
>
> Hereafter, using systems NOT running lvm, we have a bootable drive that
> can be installed into a 2nd machine and generally expect things to "just
> work" after sorting out a few driver issues. (EG: /dev/eth#s change)
> Following this exact procedure with partitions on LVM does NOT result in
> a booting system!
>
> -) When booting from the newly imaged drive, it starts the boot just
> fine but quits at:
> ----------------------------
> Activating logical volumes
>    Volume group "VolGroup00" not found
> Trying to resume from /dev/VolGroup00/LogVol01
> Unable to access resume device (/dev/VolGroup00/LogVol01)
> Creating root device.
> Mounting root filesystem.
> mount: could not find filesystem '/dev/root'
> --SNIP--
> switchroot: mount failed: no such file or directory
> Kernel panic - not syncing: Attempted to kill init!
> ----------------------------
>
>
> -) Running Linux rescue, at the shell:
> ----------------------------
> # pvscan
> PV /dev/sda2    VG VolGroup00   lvm2 [153.28 GiB / 0 free]
> Total: 1 [153.28 GiB] / inuse: 1 [153.28 GiB] / in no VG: [0  ]
> # vgscan
>    Reading all physical volums. This may take a while...
>    Found volume group "VolGroup00" using metadata type lvm2
> # lvscan
>    inactive    '/dev/VolGroup00/LogVol00' [151.31 GiB] inherit
>    inactive    '/dev/VolGroup00/LogVol01' [1.97 GiB] inherit
> ----------------------------
>
> -) Running the EL5 installer with the "Find distro" option on mounts the
> install at /tmp/sysimage without issue.
>
> What am I missing?!?!
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