[Linux-cluster] CLVM and Snapshots?

[Nate Carlson]

On Tue, 2 Aug 2005, Nate Carlson wrote:
> I'm curious if it should be possible to take a snapshot of a filesystem 
> sitting on top of CLVM (*not* a shared filesystem like GFS; something 
> like XFS or ext3, but still on a shared block device). I recall trying 
> it a couple weeks ago, and it failing miserably, but don't recall why, 
> and figured I'd ask if it should work before experimenting again.
>
> If it should work, a few questions:
> - Should I be able to create the snapshot on any node, or just the node
>  that is using the LV that I want to create a snapshot of?
> - Is the syntax identical to normal linux snapshots?
>
> Thanks!

OK, decided to try it.. here's what I get:

xen1:~# lvcreate -L 1G -s -n snaptest /dev/XenSystemDisks/iron
   Error locking on node nitrogen: Internal lvm error, check syslog
   Aborting. Failed to activate snapshot exception store. Remove new LV and retry.

Error on Nitrogen:

Aug  2 14:09:05 nitrogen lvm[295]: Volume group for uuid not found: doCTDCC376pE3g2JA35fNAieVNTWpAC1B3UIGOGQpn5Um5FcmPsa8yQPa0p9o9ZP

Nitrogen does not have access to the PV that this snapshot is on, which 
could be part of the problem.

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| nate carlson | natecars at natecarlson.com | http://www.natecarlson.com |
|       depriving some poor village of its idiot since 1981            |
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