[Samba] CTDB and NFS4

Stephen Ward sw_samba at nzgeek.com
Tue Mar 11 02:09:15 MDT 2014

Hi Volker, thank you for your comments.

Using CTDB with an NFS server if I mount with the version 3 option then
stop ctdb on the server the client fails over to the new server fine.  Same
client, same servers, same process but mounting with the version 4 option
and when CTDB fails over the client locks.  After ten minutes or so I
killed the process on the client, it was still not responsive.

As I understand it this works because the NFS daemons share records and
'tickle' connections on failover (see

 NFS4 works fine except for failover and NFS3 works fine including failover
so I assume that it is specifically an issue with NFS4 with CTDB.

My understanding of specifically how this works is limited so if anyone has
any ideas about this at all I'd be really keen to hear!

On Tue, Mar 11, 2014 at 8:30 PM, Volker Lendecke
<Volker.Lendecke at sernet.de>wrote:

> On Fri, Mar 07, 2014 at 12:32:01PM +1300, Stephen Ward wrote:
> > I'm sorry if this has already been covered somewhere, but I've had a look
> > and can't find it.  Also if there is a better place for this question,
> > please let me know.
> >
> > I know that the CTDB documentation states that only NFS2/3 are supported
> > with CTDB but what I'd really like to know is why NFS4 won't work and if
> > NFS4 support is planned for the future (timeline?).  Also can anyone
> > suggest any work arounds/development versions/anything that may help with
> > this?
> >
> > I have a cluster that works well with samba4 and NFS3 (on GPFS/RHEL) but
> > unsurprisingly, while NFS4 works ok normally, if I stop the server a
> client
> > is using any access attempts will freeze on the client.
> Is that really a NFS4/CTDB question? With hard mounts that's
> pretty much what I would expect.
> Volker
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