Terrible NFS performance under 9.2-RELEASE?

[J David]

Rick,

If iozone wants to do a 4kiB write in the middle of a 1GiB file and
the rsize/wsize are both set to 32kiB, does NFS read a 32k block over
the wire, modify it, and send it back?  Or does it just send "write
this 4k at offset X" and let the server sort it out?

Some of the tests I'm running are producing very strange results, and
I'm trying to understand what might be happening.

Thanks!