NFS network load on 5.4-STABLE

[Mike Eubanks]

On Sun, 2005-11-27 at 15:43 -0500, Kris Kennaway wrote:
> On Sun, Nov 27, 2005 at 01:27:38AM -0800, Mike Eubanks wrote:
> > On Sat, 2005-11-26 at 21:49 -0500, Chuck Swiger wrote:
> > > Mike Eubanks wrote:
> > > > As soon as I mount my NFS file systems, the network load
> > > > increases to a constant 80%-90% of network bandwidth, even
> > > > when the file systems are not in use.  NFS stats on the client
> > > > machine (nfsstat -c) produce the following:
> > > >
> > > [ ... ]
> > > > Fsstat and Requests are increasing very rapidly.  Both the client and
> > > > server are i386 5.4-STABLE machines.  Is this behaviour normal?
> > > 
> > > Sort of.  Some fancy parts of X like file-manager/exporer
> > > applications tend to call fstat() a lot, but it's probably
> > > tunable, and if you enable NFS attribute caching that will
> > > help a lot.
> > 
> >   Thank you for the reply Chuck.  It seems that it is something to do
> > with Gnome.  I haven't done an upgrade to 2.12 yet, but the difference
> > did happen when I refreshed my user configuration to remove any stale
> > config files.  Using the "top -mio" command I get the following:
> > 
> > [ ... ]
> > 
> 
> That doesn't look like it is showing a problem to me.  In particular
> it is indicating 0 I/O.
> 
> >                                      +---- file-manager/explorer?
> >                                      |
> > client.220312819 > server.nfs: 96 fsstat [|nfs]
> > server.nfs > client.220312819: reply ok 168 fsstat POST: DIR 755 ids
> > 1001/0 [|nfs]
> >
> > If this is enough evidence for the file-manager/explore,
> 
> It's evidence that something is peforming NFS I/O, but it doesn't show
> what.  Perhaps you needed to also use the top -S flag, or to sort the
> output by typing 'ototal'.
> 
> > I'll just have
> > to accept it for now.  I can't find anything about tuning them.  As far
> > as attribute caching, do you mean the `-o ac*' options to mount_nfs?  I
> > also noticed two sysctl values, although, I left them unmodified.
> > 
> > vfs.nfs.access_cache_timeout: 2
> > vfs.nfs4.access_cache_timeout: 60
> 
> Increase the former (you're not using nfs4).  Try 60 seconds, for
> example.  The downside is that you'll have to wait up to a minute for
> access changes on the server to be visible to the client, but that's
> usually not a big deal unless you're accessing a lot of dynamically
> created and destroyed files.
> 

I made the sysctl modification.  Still no luck though.  The only process
that had any activity using the top with the -S option, or after sorting
by total, was the swapper/syncer.  Even then, it was hardly active.  The
network traffic persists.

-- 
Mike Eubanks <mse_software at charter.net>