[linux-lvm] F7 will not boot after running backup w/snapshot
mpatocka at redhat.com
Sat May 3 02:27:38 UTC 2008
On Thu, 1 May 2008, Gerry Reno wrote:
> Mikulas Patocka wrote:
>> ... If you mount the origin device with missing snapshot, you destroy the
>> snapshot (even if you don't touch it). The snapshot can no longer be
> So it is safer to not activate device in this case then destroy data.
> Why? What value is the old snapshot at this point? You just had a system
> reboot in the middle of a snapshotted backup so all you need to do is get the
> system up, redo another snapshot and retake your backup. I'm not interested
> in the old snapshot.
If you use snapshots for something other than backups (for example
version-control using snapshots --- to enable admin to revert changes if
he messes something), then the snapshot is valuable and should survive
Anyway, placing a ramdisk to volume group is bad idea and it must not be
done on any production system --- note that any lvcreate, lvconvert, etc
command can allocate anything on that ramdisk --- without the
administrator knowing it.
--- so I don't see any reason why we should do extra hacks to lvm for
people who placed ramdisk into vg.
To use temporary storage for snapshot, a special command for lvm would be
more appropriate --- a command that would setup snapshot and write nothing
about it to metadata, so that the snapshot would be forgotten on next
reboot --- then, you can setup the snapshot on any device outside the
volume group. You can already do this with dmsetup.
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