On Fri, Jun 01, 2018 at 10:33:14AM -0400, Jeff Layton wrote: > On Fri, 2018-06-01 at 10:17 -0400, J. Bruce Fields wrote: > > On Fri, Jun 01, 2018 at 06:42:37AM -0400, Jeff Layton wrote: > > > Thanks for having a look. Hmm...you're right. > > > > > > nn->nfsd4_lease = 90; /* default lease time */ > > > nn->nfsd4_grace = 90; > > > > > > nit: We should probably add a #define'd constant for that at some > > > point...but, might this be problematic? > > > > > > In the pessimal case, you might renew your lease just before the server > > > crashes. It then comes back up quickly and starts the grace period. By > > > the time the client contacts the server again the grace period is almost > > > over and you may have very little time to actually do any reclaim. > > > > > > ISTR that when we were working on the server at PD we had determined > > > that we needed around 2 grace periods + a small fudge factor. I don't > > > recall the details of how we determined it though. > > > > OK, I'd be interested in any of that. > > > > If we decide we need a larger grace/lease ratio, we may want to adjust > > default lease down at same time to avoid increasing grace period, as > > that's always an annoyance. > > > > I think we just figured that we ought to give the client a full lease > period to reclaim everything, in case it holds a lot of state. You also > need to give it a full lease period to figure out that the server has > rebooted, and then I think we added a few seconds to account for "other > factors" (transport delays and whatnot). I think it would also be easy to extend it on demand. So, for example: end the grace period when: (one lease period has passed *and* we've received no reclaim request in the last second) *or* two lease periods have passed Maybe think about the exact choice of numbers a little. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
