NFS stalling on 8.1-STABLE

[Jeremy Chadwick]

On Thu, Aug 12, 2010 at 10:35:49AM -0700, Mark Morley wrote:
> I have five front end web servers that all mount their content from
> the same server via NFS.  If I stress the link on any one of the
> machines (eg: copy a large directory with a lot of files to/from the
> mounted file system) the client will pause.  That is, all processes
> trying to access that mount will freeze.  The log files with hundreds
> or thousands of nfs server not responding / is alive again messages.
> After 60 seconds it returns to normal, unless the load is still there
> in which case it continues to pause.
> 
> This has only started happening since I upgraded the client machines
> to 8.1-STABLE (previously four of them were 8.0 and one was 7.3).  The
> server is 7.1-RELEASE-p11.  No other changes have taken place in terms
> of hardware or software or mount options, etc.
> 
> All nics involved are gigabit em cards, and they are on a private
> network (web access to the boxes is via an external interface).

Are there any indications in dmesg that the NIC is responsible, e.g.
interface down/up, etc.?

Does switching to UDP-based NFS solve the problem for you?

What OS version (uname -a) and NIC are used on the NFS server?

Can you please provide the following output from one of the client
machines running 8.1-STABLE with gigE em(4)?  You can X-out machine
names, MAC addresses, and IP addresses/netblocks if need be.

* uname -a
* ifconfig emX  (where X is the interface number which would be
  used for NFS)
* netstat -idn -I emX
* pciconf -lvc  (provide only the data for emX please)
* vmstat -i
* sysctl hw.pci
* As root, run "sysctl dev.em.X.stats=1" then do "dmesg" and
  provide the output for NIC statistics (will start with "emX:")

Thanks.

-- 
| 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 |