[Sheepdog] Sheepdog Read-only issues.

[Eric Renfro]

Here's some information I'm getting regarding when the R/O remount occurs:

dmesg output:
[10925.885942] end_request: I/O error, dev vda, sector 12582912
[10925.887948] Aborting journal on device vda2-8.
[10925.889376] EXT4-fs error (device vda2): ext4_journal_start_sb: Detected
aborted journal
[10925.891753] EXT4-fs (vda2): Remounting filesystem read-only
[11369.614431] EXT4-fs error (device vda2): ext4_remount: Abort forced by
user

mount:
/dev/vda2 on / type ext4 (rw,errors=remount-ro)

remount:
root at fw1:~# mount -o remount,rw /
mount: cannot remount block device /dev/vda2 read-write, is write-protected

Eric Renfro



On Thu, Apr 7, 2011 at 2:06 AM, Eric Renfro <erenfro at gmail.com> wrote:

> Hello,
>
> I just started using Sheepdog and I'm curious as to why this is occurring,
> if it's a known issue or a resolved issue.
>
> What's happening to me is, when one of my sheep servers are taken down, it
> causes server-wide issues, especially with running VM's. I have 6 sheep
> servers running on 6 physical computers. 4 of the servers run kvm guests
> along with sheep, 2 servers are just storage servers only. I currently run
> sheepdog through pacemaker as a primitive lsb resource in every sheep node.
> When I stop pacemaker on nas2 (a storage only server), vm's on vservers 1-4
> suddenly get I/O errors and the filesystems remount R/O and either won't
> restart properly on the same node and have to be migrated to another node,
> or they do. Either way the only way to restore access is by rebooting the
> guest vm outright. Each guest vm uses the localhost:7000 for sheep access to
> the sheepdog vdi's.
>
> I'm running this platform all on OpenSUSE 11.4 with qemu 0.14.0 from
> standard opensuse repositores (not the virtualization repository) and
> reasonably current sheepdog git build.
>
> I setup the sheepdog collie cluster to maintain 3 copies as well.
>
> In another test, I had just 2 vservers running sheepdog with vm guests on
> the same 2, using only 2 copies, during my initial testing of sheepdog, and
> by crowbarring pacemaker into standby mode to test migration of the kvm
> sessions, it ended up destroying the sheepdog cluster completely loosing all
> of the vdi's, and being unable to find a specific obj file it was looking
> for from the cluster so it kept trying endlessly. Ended up having to
> reformat the cluster, which is when I got my two storage servers rebuilt to
> handle 2 more sheep clusters and set it up to use 3 copies amongst 4
> servers, then finally the 2 other vservers were joined into the sheepdog
> cluster as a whole.
>
> Any information regarding this problem I'd be glad to hear it. So far it
> looks like Sheepdog is going to be very strong and powerful and meet my
> needs, as long as I can get around this current problem I have presently.
>
> Eric Renfro
>
>
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