process stuck in nfsfsync state
Joan Picanyol
lists-freebsd-stable at biaix.org
Mon Oct 25 09:11:51 PDT 2004
* Robert Watson <rwatson at freebsd.org> [20041025 14:24]:
>
> On Mon, 25 Oct 2004, Joan Picanyol wrote:
>
> > > Is there an response to the request? If not, that might suggest the
> > > server is wedged, not the client. If you are willing to share the results
> > > of a tcpdump -s 1500 -w <whatever> output from a few seconds during the
> > > wedge, that would be very useful.
> >
> > Available at http://biaix.org/pk/debug/nfs/ These are from just after
> > logging in to GNOME until gconfd-2 goes to nfsfsync, and the nfs server
> > not responding messages start appearing.
>
[snip *much* appreciated detailed analysis]
> So if possible, I might try some of the following:
[...]
> - I think someone already suggested disabling hardware checksumming, but
> if you haven't tried that, it would be worth trying it.
No difference.
> - It would be useful to see if less complicated NFS meta-transactions than
> "Start GTK" can trigger the problem. For example, doing a large dd to a
> file in NFS, varying the blocksize to see if you can find useful
> thresholds that trigger the problem. I see a lot of successful 512 byte
> writes in the trace, but larger datagram sizes of 8192 for writes seem
> to have problems.
Now this is interesting:
dd if=/dev/urandom of=/fs/bulk/mount/dummy bs=512 count=14
wedges the NFS mount point 100% of the times. Lowering the count to 13
doesn't reproduce the hang.
An another possibly interesting data point is that NFS over TCP works
ok. For this I'm particularly grateful, since I can now mount my /home
fs and do my work.
Am I the only one seeing this?
tks
--
pica
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