NFS 75 second stall

[Jeremy Chadwick]

On Thu, Jul 01, 2010 at 11:01:04AM -0700, alan bryan wrote:
> Setup:
> 
> server - FreeBSD 8-stable from today.  2 UFS dirs exported via NFS.
> client - FreeBSD 8.0-Release.  Running a test php script that copies around various files to/from 2 separate NFS mounts.
> 
> Situation: 
> 
> script is started (forked to do 20 simultaneous runs) and 20 1GB files are copied to the NFS dir which works fine.  When it then switches to reading those files back and simultaneously writing to the other NFS mount I see a hang of 75 seconds.  If I do an "ls -l" on the NFS mount it hangs too.  After 75 seconds the client has reported:
> 
> nfs server 192.168.10.133:/usr/local/export1: not responding
> nfs server 192.168.10.133:/usr/local/export1: is alive again
> nfs server 192.168.10.133:/usr/local/export1: not responding
> nfs server 192.168.10.133:/usr/local/export1: is alive again 
> 
> and then things start working again.  The server was originally FreeBSD 8.0-Release also but was upgraded to the latest stable to see if this issue could be avoided.
>
> ...
> 
> Any ideas on what's going on here?  What's causing the complete stall period of zero NFS activity?   Any flaws with my testing methods?

One thing worth asking: are there any firewall stacks (ipfw, ipfilter,
or pf) in use on either the client or server?

-- 
| Jeremy Chadwick                                   jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |