[linux-lvm] Re: ext3 on an logical volume - snapshot using how?
Stephen C. Tweedie
sct at redhat.com
Mon Apr 8 10:02:02 UTC 2002
On Mon, Apr 08, 2002 at 03:53:17PM +0200, Ph. Marek wrote:
> I'm using LVM and ext3 and am very satisfied with it.
> But now I have the following problem:
> I have a filesystem on a LV which is in use -
> files are created, modified and so on.
> To do a backup I'd like to create a snapshot
> of this volume which gets backup'd and then dropped.
> mount: wrong fs type, bad option, bad superblock on /dev/vg/snapshot,
> or too many mounted file systems
> > EXT3-fs: INFO: recovery required on readonly filesystem.
> > EXT3-fs: write access unavailable, cannot proceed.
> If the snapshot wasn't ro I'd do a tune2fs or e2fsck or something.
There is a "VFS-lock" patch distributed with the LVM sources, which
adds code to LVM to tell filesystems to quiesce themselves for a
snapshot. This results in a filesystem which can be mounted safely
Ext3 already supports this functionality, but the LVM code in the main
kernel does not have the code to call it. The VFS-lock patch adds
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