NFS lockups with VMware esxi client

[Rick Macklem]

> I have NFS sharing a ZFS pool that VMware esxi stores files on. When
> put under stress (an OS installation, but not Linux compilation), the
> NFS server locks, spiking to 100% CPU usage. Not even kill -KILL can
> stop the process, so rebooting is required.
> 
> PID USERNAME THR PRI NICE SIZE RES STATE C TIME WCPU COMMAND
> 885 root 4 44 0 5804K 988K CPU2 0 239:39 100.00% nfsd
> 
> Other people have run into this problem, but I never found a solution.
> I'm running 8.1-PRERELEASE on amd64, but I think others have seen the
> problem on 8.1-RELEASE.
> 
> zpool status reports that the pool is healthy, so that's not it. My
> only two ideas are hosting on something other than ZFS and trying to
> reproduce it with a lot of big, random NFS requests. Any other ideas?
> 
I believe it is patched in head/current. A compatible patch is at:
   http://people.freebsd.org/~rmacklem/freebsd8.1-patches/replay.patch

rick