12.04: NFS server stops responding, shows high CPU use in top

[IndieRockSteve]

I upgraded some components on my "fileserver" at home and now when other machines are accessing files over it the nfs server will stop responding and when I look at top there are ~5nfs processes that are using up a lot of CPU time. then the mount on the client goes stale and I have to umount -l the nfs mounts and remount after restarting the nfs-kernel-server on the "fileserver"

there does not seem to be much if any nfs logging so the best I can get is the following:

from the kernel log:
Aug 8 10:17:02 fileserver kernel: [643200.350502] nfsd: last server has exited, flushing export cache
Aug 8 10:17:03 fileserver kernel: [643201.402080] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Aug 8 10:17:03 fileserver kernel: [643201.402105] NFSD: starting 90-second grace period
Aug 8 11:17:03 fileserver kernel: [646800.796754] nfsd: last server has exited, flushing export cache
Aug 8 11:17:04 fileserver kernel: [646801.863211] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Aug 8 11:17:04 fileserver kernel: [646801.863234] NFSD: starting 90-second grace period
Aug 8 12:17:03 fileserver kernel: [650400.625576] nfsd: last server has exited, flushing export cache
Aug 8 12:17:04 fileserver kernel: [650401.723441] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Aug 8 12:17:04 fileserver kernel: [650401.723467] NFSD: starting 90-second grace period
Aug 8 13:03:00 fileserver kernel: [653158.358880] nfsd: last server has exited, flushing export cache
Aug 8 13:03:01 fileserver kernel: [653159.476823] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Aug 8 13:03:01 fileserver kernel: [653159.476848] NFSD: starting 90-second grace period


anyone have *any* idea what's going on or how to enable some sort of useful logging in NFS to figure out why this is happening?

[Ladislav Dobias]

I have the same problem on 12.04 LTS. I had it also on 10.04 LTS. I do not use NFS much, but this is a big problem when I want to use it.

As a workaround, I just restart nfs-kernel-server, and the NFS client just continues to work (e.g. play mp3). It happens about every 1 to 5 minutes.

I have 4 core AMD Athlon(tm) II X4 630 Processor, if that matters.