[Beowulf] max number of NFS threads: NFS config optimization

[Alex Chekholko]

On Thu, 18 Dec 2008 13:59:06 -0600
"Rahul Nabar" <rpnabar at gmail.com> wrote:

> For a while I've been seeing errors of this sort in my /var/log/messages
> 
> kernel: nfsd: too many open TCP sockets, consider increasing the number of
> nfsd threads
> 
> I googled a bunch and think the solution might be to boost RPCNFSDCOUNT in
> the line "[ -z "$RPCNFSDCOUNT" ] && RPCNFSDCOUNT=8"  in the file
> /etc/init.d/nfs.
> 
> Question: This seems a suspicious place to change it. Isn't there a nfs
> config file somewhere else?
> 
> Question2: How high can I boost the number of NFS threads? Or how I should
> I? Is there any metric I can track to decide an optimum number? Most
> recomendations were for 32, 64 or 128. What do people suggest? Any
> downsides to having numbers that are too high?
> 
> In case it matters, this is our master-node Linux server and has the
> /home directories for each user
> exported to about 200 odd compute-nodes.

On EL, there's /etc/sysconfig/nfs, and /etc/defaults/nfs-kernel-server
on Debian-based systems.

Up it to 32, see if you keep getting the message? :)

Also check that you're actually running just 8:
ps auxf|grep nfs

Regards,
-- 
Alex Chekholko   chekh at pcbi.upenn.edu