nfs server not responding / is alive again

[Marc G. Fournier]

I'm using an nfs mount to get at the underlying file system on a system 
that uses unionfs mounts ... instead of using nullfs, which, last time I 
used it over a year ago, caused the server to crash to no end ...

But, as soon as there is any 'load', I'm getting a whack of:

Oct  3 22:46:16 neptune /kernel: nfs server neptune.hub.org:/vm: not responding
Oct  3 22:46:16 neptune /kernel: nfs server neptune.hub.org:/vm: is alive again
Oct  3 22:48:30 neptune /kernel: nfs server neptune.hub.org:/vm: not responding
Oct  3 22:48:30 neptune /kernel: nfs server neptune.hub.org:/vm: is alive again

in /var/log/messages ...

I'm running nfsd with the standard flags:

 	nfs_server_flags="-u -t -n 4"

Is there something that I can do to reduce this problem?  increase number 
of nfsd processes?  force a tcp connection?

The issue is more prevalent when I have >4 processes trying to read from 
the nfs mounts ... should there be one mount per process?  the process(es) 
in question are rsync, if that helps ... they tend to be a bit more 'disk 
intensive' then most processes, which is why I thought of increasing -n 
...

Thanks ...

Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy at hub.org           Yahoo!: yscrappy              ICQ: 7615664