[linux-lvm] snapshot error with xfs and disk I/O
wim at unetix.nl
Fri Mar 31 14:21:22 UTC 2006
>On Thu, Mar 30, 2006 at 09:09:22AM +0100, Wim Bakker wrote:
>> There seem to be serious problems with snapshots , lvm2 and xfs.
> >As soon as there is a slight amount of disk I/O during snapshotting
> >a logical volume with xfs , the following kind of kernel panic occurs:
>You don't say what kernel.
>Make sure it contains the dm snapshot patches from -mm (and probably
>in Linus's git tree by now - I haven't checked).
On the original server 2.6.15 was used, on the test server I installed
2.6.16 with pending patches :
as found in
and conform a recommendation I read in the mail archives regarding the
problems with snapshots (and xfs?).
Version of lvm is : LVM2.2.02.02
Version of dm is : device-mapper.1.02.03
The snapshot is mounted under backup , the original LV is mounted under data
and the files that give I/O errors under backup are perfectly accessable on
the original LV. There is a script in the background running that randomly
creates files test-* and testfile-* on the data partition.
Meanwhile I have going on with some testing , to that end I installed kernel
2.4.32 with the dm and lock patches , reinstalled the latest lvm2 stable and
dm stable. And ran under 2.4.32 the same tests as under 2.6.16 with the
extra pending patches.
I restarted the system with 2.4.32 and ran the same tests as with 2.6.16
and no problems occurred at all.
Then I restarted the system again with kernel 2.6.16 , and lvremove locked up
again with the resulting kernel panic when forcefully removing the snapshot
volume , like before. I than restarted again with kernel 2.4.32 and all tests
and snapshots run smoothly, so it seems definitely related to kernel 2.6.x.
For the production machine we need definitely 2.6 though because of the areca
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