[Beowulf] Looking for NFS Server performance comparison

[Joachim Worringen]

Bill Rankin wrote:
> Hi Gang,
> 
> This may be a rehash, but I'm looking for any references to papers  that 
> address the issue of NFS server scalability in a cluster  environment.  
> Our current cluster here at Duke is right at 500 nodes  (and growing) 
> and the single NFS server with attached SCSI drives  serving all data to 
> all nodes just doesn't seem to hack it anymore.
> 
> I know that there are clustered solutions like PVFS, IBRIX, et. al.  as 
> well as the dedicated filer approach (NetApp, EMC, etc.) and we  are 
> looking at those. But first we need to convince the powers that  be that 
> a Linux-based NFS server just ain't going to cut it as we  move forward.

Hi Bill,

sorry if this sounds a bit perky, but: if you have I/O bound applications, I'm 
quite sure you can show that they don't scale even with the current 500 nodes on 
a single NFS server. And if you don't have such applications - well, than you 
don't have a problem... ;-) You can still use a benchmark, but this might not 
convince "the powers".

Above you say that the NFS server has already problems now: shouldn't that 
convince the powers that you need something else than NFS? Which problems do you 
refer to with "doesn't hack it anymore"?

Correct me if I just didn't understand your problem. However, I *do* understand 
that NFS really is a bad idea for many nodes doing something else than just 
loading the executable (and even this may show problems at scale). Ie. doing 
MPI-IO correctly is a nightmare on NFS.

> So if anyone knows of good documents (white papers, conference  papers, 
> etc.) that will support my assertion, I would appreciate a  pointer to 
> them.

I'm quite sure the vendors will happily provide you with such material... A 
quick search gave this GPFS vs. NFS evaluation: 
http://www.nus.edu.sg/comcen/svu/publications/hpc_nus/sep_2005/Performance.pdf

  Joachim

-- 
Joachim Worringen - NEC C&C research lab St.Augustin
fon +49-2241-9252.20 - fax .99 - http://www.ccrl-nece.de