Re: NFSv4 high availability setups

[Lukas Hejtmanek <xhejtman@ics.muni.cz>]

Hi Jeff, 

On Thu, Apr 05, 2012 at 07:39:01AM -0400, Jeff Layton wrote:
> > As I understand, NFS4 uses state dir somewhere in /var/lib/nfs/rpc_pipefs.
> > 
> 
> You're probably thinking of /var/lib/nfs/v4recovery.

yes, sorry for confusion.

> > Can we put this state dir on a shared volume so that this state dir is common
> > for all the front-ends serving the same content? Is is supposed to work and
> > NFSv4 can merge its state with existing state on a shared disk?
> > 
> 
> Not properly, no. nfsd expects to have complete control over that
> directory. There's no locking or merging of the data there. A node will
> also clean that directory out in some cases, and that will throw your
> state tracking off.

Thank you for information.

Is there any (preferably simple) way to demonstrate that this does not work
properly? E.g., if I share the same export through two or more NFSv4
front-ends that share the v4recovery directory, do I trigger problems with
this tool http://nfsv4.bullopensource.org/tools/tests/locktest.php?

-- 
Lukáš Hejtmánek