Client Lockups

[IHE Lists <ihelists@gmail.com>]

Here's the situation:

We have a multithreaded Java application that does a great deal of IO
over NFS. Almost daily, sometimes several times within a single day,
we get an application deadlock. The error in the kernel syslog message
is:

Dec 11 11:09:05 <hostname> kernel: RPC: error 512 connecting to server
<NFS server>

This error repeats numerous times.

The client mount options are:

rw,hard,intr,rsize=8192,wsize=8192,noatime,nfsvers=3,tcp,timeo=600,retrans=2

We have a deadlock monitor that attempts to restart the application by
first sending the process a "kill -9", then running the init.d script.
Of course, the threads stuck in the D state do not die, so the restart
fails. This cycle continues for almost 25 minutes (almost
consistently) before it succeeds.

I believe the eventual total deadlock is a problem in the Java virtual
machine, but I cannot determine what is causing the problem to begin
with. Other applications on the same system do not lockup accessing
other NFS mounts.

I've seen this problem on a custom kernel running 2.4.20 with the -aa1
patches and all the other applicable 2.4.20 patches from Trond and
Neil. I've also seen it occur on SLES8 kernels 2.4.21-241, 2.4.21-251,
and 2.4.21-261. Our systems are somewhat custom, so they are all
running nfs-utils 1.0.6, but the base is currently Red Hat 7.3.

I guess my primary question is: this a kernel problem, an nfs-utils
problem, or does the problem lie somewhere else?

Any help is greatly appreciated!

-Brian


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/
_______________________________________________
NFS maillist  -  NFS@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/nfs