On Wed, Jul 28, 2010 at 09:44:48AM -0400, Jason Keltz wrote: > Hi. > > My list of NFS exports has been gradually growing over the years. > Right now, for example, my home directories are exported to around > 800 hosts. (although only a relatively small subset of those will > mount at the same time...). I used to just add hosts to > /etc/exports on the file server, and run "exportfs -r", and > everything would be fine. New systems would be able to mount > everything perfectly, and existing systems would not be affected at > all. As the list has grown, I've been noticing a problem. Now, when > I run exportfs -r, there is an approximate 7-10 second hang on the > systems that have already mounted the share, and then everything > returns to normal. This doesn't happen *while* exportfs -r is > running, but just after it exits. I figured that maybe exportfs was > "unexporting"/re-exporting to hosts that already had the share in > use which might have caused the problem, so I tried to manually > add/remove hosts thinking that this would only affect those hosts, > but it did not. Exporting to one new host still causes the hang on > all existing hosts. > > Since I have multiple exports to all of the hosts, adding one new > host can hang things for a while. I can see that reducing the list > of exports, or hosts would reduce the delay. What I am wondering is > if there is a better way that I can add hosts without affecting > connectivity to existing hosts? > > The NFS server itself is pretty powerful -- dual quad core box, lots > of memory, many NFS threads, exclusive NFS server, etc... I am > running an older RHEL4 release though, so it would have an older > kernel/NFS system. Maybe this issue has been solved in newer > releases. There have been fixes in this area, though I don't see any that I'm sure would address your problem. If you could test with the latest nfs-utils (ideally, with the latest nfs-utils and kernel) and let us know the result, that would be helpful. The -t option to rpc.mountd (may need a newer nfs-utils?) may also help. Also worth filing an RHEL bug. --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
