Re: cannot use btrfs for nfs server

Ulli Horlacher
2021-07-12T07:32:37Z

On Sat 2021-07-10 (16:17), Chris Murphy wrote:
> On Sat, Jul 10, 2021 at 12:56 AM Ulli Horlacher
> <framstag@rus.uni-stuttgart.de> wrote:
>
> > root@tsmsrvj:# snaprotate -v test 5 /data/fex/spool
> > $ btrfs subvolume snapshot -r /data/fex/spool /data/fex/spool/.snapshot/2021-07-10_0849.test
> > Create a readonly snapshot of '/data/fex/spool' in '/data/fex/spool/.snapshot/2021-07-10_0849.test'
>
> I think this might be the source of the problem. Nested snapshots are
> not a good idea, it causes various kinds of confusion.

I do not have nested snapshots anywhere.
/data/fex/spool is not a snapshot.
/data/fex/spool/.snapshot/2021-07-10_0849.test is a simple snapshot of
the btrfs subvolume /data/fex/spool

> > We cannot move the snapshots to a different directory. Our workflow
> > depends on snaprotate:
> >
> > http://fex.belwue.de/linuxtools/snaprotate.html
>
> OK does the problem happen if you have no nested snapshots (no nested
> subvolumes of any kind) in the NFS export path?
>
> If the problem doesn't happen, then either the tool you've chosen needs
> to be enhanced so it will create snapshots somewhere else, which Btrfs
> supports, or you need to find another tool that can.

Without snapshots there is no problem, but we need access to the snapshots
on the nfs clients for backup/recovery like Netapp offers it.
But Netapp is EXPENSIVE :-}

If we cannot handle it with btrfs, then we have to switch to ZFS.

--
Ullrich Horlacher Server und Virtualisierung
Rechenzentrum TIK
Universitaet Stuttgart E-Mail: horlacher@tik.uni-stuttgart.de
Allmandring 30a Tel: ++49-711-68565868
70569 Stuttgart (Germany) WWW: http://www.tik.uni-stuttgart.de/
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