Re: NFSv4 high availability setups

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

Hi,

On Tue, Apr 10, 2012 at 09:13:21AM -0400, Jeff Layton wrote:
> Nope. It'll all work just great...until it doesn't. I don't have any
> specific failure scenarios, but most of the problems will be issues
> with state recovery when a server node is restarted.
> 
> That may manifest in different ways -- problems reclaiming locks for
> instance, or even silent data corruption depending on the application.

would it work if I relax active-active scenario to just active-passive in the
following way:

Server A actively exports  /export/A
Server B actively exports  /export/B

Server B is passive backup for Server A
Server A is passive backup for Server B

would it work to migrate the failed Server B to Server A so that Server A will
server both /export/A and /export/B?

There will be a problem with v4recovery dir. Would it be possible just to
merge v4recovery from Server B to Server A (nfs export would be stopped while
merging v4recovery).

It seems that cp -r B/v4recovery/* A/v4recovery/ would do all the things. Am
I right?

Do I need to copy recovery state if I delay migration of the failed Server B to
Server A for 91 secs? I.e., longer than lease expiry time.. Or do I still need
a record for the client in v4recovery dir in such a case?

-- 
Lukáš Hejtmánek