[linux-lvm] summary of what I need to do to mount snapshot on XFS
Adrian Head
ahead at bigpond.net.au
Wed Jan 9 17:39:01 UTC 2002
If this works for you - good. I have had heaps of issues that I have been
working with various developers and trying to get fixed.
Basically if I used the SGI 2.4.17-xfs kernel with lvm-1.0.1rc4(ish) some
file systems would work but others would fail. Some would fail on snapshot
creation, others would fail on snapshot mount and others would fail when the
snapshot overflowed. When I upgraded LVM to lvm-1.0.1 other filesystems
issues were fixed but others broke again. Check out the "Unable to get XFS,
ext3, reiserfs & LVM to coexist happily"
http://marc.theaimsgroup.com/?l=linux-lvm&m=100994364215110&w=2
thread on linux-lvm / linux-xfs mail archives and see if any of this relates
to your problem. With 2.4.17-xfs + lvm-1.0.1 upgrade patch + VFS-lock patch
ext2/3 & resierfs will operate correctly but XFS will fail at snapshot
creation. You can do a little source code change and get a XFS snapshot
created and mounted; but then it will fail on an overfull snapshot. These
problems are being worked on by myself and the great SGI XFS developers.
The lvm.c change you talk about I assume is the LVM_VFS_ENHANCEMENT change?
For some reason when adding the lvm-1.0.1 upgrade patch this disappears from
lvm.c I have been able to get this to compile with the change but I have
forgoten what I did.
This is one question I would like answered by the LVM gurus: should #define
LVM_VFS_ENHANCEMENT still be there after upgrading to lvm-1.0.1? What does
LVM_VFS_ENHANCEMENT actually do w.r.t lvm-1.0.1rc4(ish) and lvm-1.0.1? I
know that LVM_VFS_ENHANCEMENT in older LVM versions was the locking of the
VFS so that snapshots would be consistant - is this still correct and is it
still needed?
For the "large discussion" you are talking about the "Unable to get XFS,
ext3, reiserfs & LVM to coexist happily" thread - hit me off list and I will
attempt to summarise it for you.
On Thu, 10 Jan 2002 06:09, Jeremy Hansen wrote:
> My issue wasn't so much with how to create the snapshot but how to
> simultaneously mount the snapshot with the live filesystem. I saw a big
> thread about having to uncomment from lvm.c, did that but then got
> unresolved symbols...
>
> It seemed as if there were some issues and a large discussion related to
> doing this with XFS.
>
> Thanks
> -jeremy
--
Adrian Head
(Public Key available on request.)
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