We have been having a nasty problem with I/O errors from AFS.  When I
posted a note about this a while back, we were able to replicate the
problem only with the 'mkisofs' CDROM mastering utility.  Now, we have
been able to replicate it with 'tar'.

Our servers are RS6000 model 530's.  The client platform most likely
to produce the problem is an RS6000 model 320 with minimal AFS cache.
A 'tar' of a mixture of large (~ 100MB) and small files in AFS will
fail with an I/O error.  I suspect that directing the output of the
'tar' to a file in AFS will make failure more likely.

No disk hardware error is found in the system error log.

During the 'tar', 'fs getcacheparms' produces the following worrisome
output:

 AFS using 189273 of the cache's available 163840 1K byte blocks.
 [Cache guideline temporarily deliberately exceeded; it will be adjusted down but you 
may wish to increase the cache size.]

We set our cache size to 80 percent of the size of the dedicated AFS
cache partition.  Lowering this to 70 percent does not prevent the
problem.

We are running AIX 3.2.5 and AFS 3.4a-patches.

To my knowledge, the problem has been replicated at one other site.

I have filed a report with Transarc (TR-23696), but I think it would
help if other sites were able to replicate the problem and filed
reports.

The only reasons I can think of why other sites might not have
encountered this problem are that most sites use AFS 'backup' instead
of tar, and that the problem may be platform-specific or
server-performance-related.

Thanks in advance for any help.
-Rick

-- 
|Rick Cochran                                         phone: 607-255-7223|
|Cornell Materials Science Center                       FAX: 607-255-3957|
|E20 Clark Hall, Ithaca, N.Y. 14853           email: [EMAIL PROTECTED]|
| "The Founding Fathers did not establish the United States as a         |
| democratic republic so that elected officials would decide trivia,     |
| while all great questions would be decided by the judiciary."          |
|                                       Judge Andrew Kleinfeld           |

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