NFS mount stops allowing file create below 4 dir levels deep

[Dana IT Unix Sysmgt.Tea]

Configuration is NFs server running HPUX 11.11 on RP8420 and NFS client running HPUX 11.31 on Superdome
The NFS client has a file system mounted (several mounted - but only one had this issue) by automount at bootup. Before Jan. 10 the FS was mounted by a manual mount instead of through autofs. As of Jan. 10 reboot the FS was mounted by autofs
For several days this mount worked fine. We have a process that regularly writes files on that mount (at least one every 30 minutes, sometimes more). Then on Jan. 13 at about 5 AM that process attempted to create a file on the mount and it hung (no error - it just hung until killed). From that point on any process that attempted to write there hung. After testing we found that we could write files to any dir that was four or less levels deep (NFS mount is at one level off /). But, any attempt to create a file another level deep hung. We could edit or remove files with no problem. But, we could not create a file (via vi, or redirect output to new file name, mkdir, etc.).
We stopped the process that writes to the mount point regualrly and shortly after autofs unmounted the file system. Then when we accessed it (from shell) autofs mounted it and we were able to create files at any level with no problem.
We have not been able to recreate the problem on this or our test 11.31 servers. There were no syslog, dmesg, etc. message that were received at the time this started. We would like to make sure that we have all necessary NFS and automount patches applied to try to assure that this does not happen again.

Has anyone seen anything like this or does anyone have suggestions what to look for?

Thanks.

[cnb · Accepted solution]

Run a patch assessment:

http://www11.itrc.hp.com/service/patch/assessSystemsPage.do?BC=main|

Or use SWA if installed:

# swa report

Rgds,

[Dave Olker]

> We would like to make sure that we have
> all necessary NFS and automount patches
> applied to try to assure that this does
> not happen again.

On 11i v3 (11.31) all NFS and AutoFS patches are delivered via an ISU bundle called ONCplus. ONCplus bundles are maintained here:

http://software.hp.com/portal/swdepot/displayProductInfo.do?productNumber=ONCplus

The latest version is B.11.31.08.

Regards,

Dave