Storage Agent's tape dismounted before it is finished with it.

2006-08-02 11:01:34
Subject: Storage Agent's tape dismounted before it is finished with it.
From: John Schneider <Schneider_JohnD AT EMC DOT COM>
Date: Wed, 2 Aug 2006 11:00:12 -0400
    Sorry if this is a repeat of a previous post, but I did not see my post
appear on the list, and received no responses, so I am trying again.
    I have a customer running TSM server with SAN Storage Agents at
that same level.  It is a TSM library sharing environment with a STKL700
w/9940B drives.  We are getting an unusual circumstance on one of our
Storage Agent clients that is backing up a large Oracle database.  After
mounting two tapes on two drives and backing up to them, eventually the
tapes fill up and then another tape gets mounted as needed. This works fine
for a few tapes, but then it seems as if the TSM library manager issues a
dismount of one of the drives before the client has finished writing to it.
When the client gets to the end of the tape it gets an error because the
tape gets dismounted out from underneath it.  At least, we THINK that is
what is happening.  When you query the TSM server, it still says the tape is
mounted, and doesn't give any messages except for when the client eventually
    This may not have anything to do with it, but we think we are in a part
of the backup where a single very large file (hundreds of GB) is being
written, so that it will span a tape. 
    Is the polling done between the agent and the server continue even when
one very large single file is being written?  Is it possible that the server
has decided that the client is idle, and takes its mount point away from it?
I was reading about IDLETIMEOUT and RESOURCETIMEOUT and the relationship
between them.  I believe we are just allowing them to default.  Would it
help to bump them up to prevent this?  
    Has anyone seen this behavior?

Best Regards,


John D. Schneider
Technology Consultant - Backup, Recovery, and Archive Practice

EMC² Corporation, 600 Emerson Road, Suite 400, St. Louis, MO 63141 
Cell: 314-225-9997 Email: Schneider_JohnD AT emc DOT com


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