Improving FreeBSD NFS performance (esp. directory updates)

[Tom Limoncelli]

I have a NFS server with (so far) a single NFS client.  Things work 
fine, however if (on the client) I do an "rm -rf foo" on a large (deep 
and wide) directory tree the tty receives "NFS server not 
responding"/"NFS server ok" messages.

I don't think the network is at fault, nor is the server really going 
away.  I think the client is just impatient.  Is there a way to speed 
up a large "rm -rf"?  I have soft-writes enabled but alas....

Details:
The server is an Intel Xeon CPU 2.20GHz running FreeBSD 4.8 (updated to 
the latest RELENG_4_8 release yesterday).  It has a 1000TX interface to 
a Cisco switch.  The partition is part of a SCSI RAID unit (160MB/s 
transfer rate, Tagged Queueing enabled).  The partition that is 
exported to the client is:

	# mount | egrep e2
	/dev/da0s1f on /e2 (ufs, NFS exported, local, soft-updates)

/etc/rc.conf lists:
	nfs_server_flags="-u -t -n 16"

The client is a (accoriding to dmesg) "Pentium III/Pentium III 
Xeon/Celeron (934.99-MHz 686-class CPU)" running FreeBSD 4.7-RELEASE.  
amd is configured to mount the partion with 
"opts:=rw:nfs_proto=udp;nfs_vers=3".
/etc/rc.conf lists:
	nfs_client_flags="-n 4"

Any tuning suggestions?

--tal