From: Gunnar Hilling <fedora.gunnar@hilling.de>
Date: Thu, 16 Sep 2004 02:36:47 +0200
Message-Id: <1095295007.4750.8.camel@nelson.hilling.de>
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Subject: [linux-lvm] snapshot on 6.8.5/FC development
Reply-To: LVM general discussion and development <linux-lvm@redhat.com>
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To: linux-lvm@redhat.com

Hello,

I just tried the lvm2/dm-snapshot feature and failed miserably...
After reading some older postings in this and the dm-devel mailing lists
I'm not sure what to do:

setup:
lvm2-2.0.21
kernel-2.6.8
xfs

VG-Size: 4G on Raid-Mirror (/dev/md1)
LV-Size: 1G

Calling:

lvcreate --snapshot --size 100m --name snap /dev/TestMirrorGroup/OnlineVol

will block forever. I have to reboot the computer. After
that /dev/TestMirrorGroup/snap is there...

I froze xfs before (xfs_freeze -f)

Any Clue? Is this related to xfs-FS only or do there exist general
problems (I read somewhere about problems snapshotting raids...)

BTW: Why isn't it possible to create the snapshot on another VG than the
original. This would be quite nice becauce in a typical setup it could
be an advantate to have the snapshot on a small extra disk, keeping the
original data separated from the writes to the snapshot.

Any help appreciated,

-Gunnar