Re: starting 90-second grace period

J. Bruce Fields
2009-12-11T19:50:45Z

On Fri, Dec 11, 2009 at 01:20:43PM -0500, Trond Myklebust wrote:
> On Fri, 2009-12-11 at 23:39 +0530, Tharindu Rukshan Bamunuarachchi
> wrote:
> > then why is it 90 by default ... is it RFC/Protocol requirement ?
>
> The purpose of the grace period is to give the clients enough time to
> notice that the server has rebooted, and to reclaim their existing locks
> without danger of having somebody else steal the lock from them.
>
> It is not a protocol requirement, but it is definitely a strongly
> recommended feaature if you don't want to see corruption in your
> mailbox/database/logfile/... that relies on those locks.

There are a few things we could do to lessen the pain of the grace
period, though--such as ending it when we know it's done. (In the v4
case, that's just when we know there are no clients to recover state; in
the v4.1 case, that's when all the RECLAIM_COMPLETE's are done.)

I'm hoping to work on that for 2.6.34.

--b.