NFS Locking Issue

[Garance A Drosihn]

At 9:13 PM -0400 7/1/06, Francisco Reyes wrote:
>John Hay writes:
>
>>I only started to see the lockd problems when upgrading
>>the server side to FreeBSD 6.x and later. I had various
>>FreeBSD clients, between 4.x and 7-current and the lockd
>>problem only showed up when upgrading the server from
>>5.x to 6.x.
>
>It confirms the same we are experiencing.. constant
>freezing/locking issues.  I guess no more 6.X for us.. for
>the foreseable future..

I don't know if this will be of any help to anyone,
but...

I recently moved a network-based service from a 4.x machine
to a 6.x machine.  Despite some testing in advance of the
switch, many people had problems with the service.  I booted
to a somewhat out-of-date snapshot of 5.x on the same box.
I still had problems, but it didn't seem as bad, so I stuck
with the 5.x system.  Some problems turned out to be bugs
in the service itself, and were eventually found and fixed.

However, one set of problems on that out-of-date snapshot
of 5.x were solved by adding:

net.inet.tcp.rfc1323=0

to /etc/sysctl.conf.  The guy who suggested that said it
avoided a bug which was fixed in later versions of either
5.x or 6.x, I forget which.  Of interest is that the bug
was such that some people connecting to the service were
never bothered by the bug, while other people could not use
the service at all until I turned off tcp.rfc1323 .

I have a test version of the same service running on a
different FreeBSD/i386 box, and that box is now updated
to freebsd-stable as of June 10th.  Lo and behold, someone
connecting to that test box reported some problems.  So I
typed in 'sysctl net.inet.tcp.rfc1323=0', and his problem
immediately disappeared.  So, it might be that there is
still some problem with the rfc1323 processing, or that the
bug which had been fixed has somehow been re-introduced.

In any case, people who are experiencing problems with NFS
might want to try that, and see if it makes any difference.
It does strike me as odd that some people are having a *lot*
of trouble with NFS under 6.x, while others seem to be okay
with it.  Perhaps the difference is the network topology
between the NFS server and the NFS clients.

Obviously, this is nothing but a guess on my part.  I am
not a networking guru!

-- 
Garance Alistair Drosehn            =   gad at gilead.netel.rpi.edu
Senior Systems Programmer           or  gad at freebsd.org
Rensselaer Polytechnic Institute    or  drosih at rpi.edu