IC72761: PERFORMANCE DEGRADATION WHEN VOLUME HISTORY FILE IS LARGE

APAR status

• Closed as documentation error.

Error description

• Tivoli Storage Manager server might perform poorly during backup
  or during other processes that use a lot of sequential
  volumes. This may be due to a large volume history file. When
  opening a volume, the server may need to check the volume
  history table to see if the volume is already used.
  If the volume history file is large, the server may spend an
  excessive amount of time searching it.
  This can potentially cause other sessions or processes to be
  delayed due to locking.
  
  It is recommended to regularly prune entries from the volume
  history file using the DELETE VOLHIST command.
  The performance tuning , and Administrator guide should be
  updated to make this recommendation.
  
  Tivoli Storage Manager Versions Affected:
  
  All supported version
  
  Customer/L2 Diagnostics :
  
  An instrument trace show a lot of time spent in "Tm Lock Wait"
  .
  This may be common when using a lot of small FILE sequential
  volumes
  
  
  Initial Impact: Medium
  
  Additional Keywords:
  perf tsm ZZ61 ZZ62 volh volhistory lock deadlock hang
  

Local fix

• Create an administrator schedule for the DELETE VOLHIST command
  to clean unneeded volhist entries like STGnew, STGDelete,
  STGReuse  .
  It is not necessary to keep those entries more than a couple of
  weeks before the older DBBackup .
  Also consider deleting other types of entries if there are many
  of them.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Tivoli Storage Manager users.            *
  ****************************************************************
  * PROBLEM DESCRIPTION: See error description.                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  *
  

Problem conclusion

• The following text will be added to the  Administrator's Guides
  and the Performance Tuning Guide:
  
  The Tivoli Storage Manager server performance might be degraded
  during backups and other processes that use many sequential
  volumes. This condition can be cause by a very large
  volume history table in the database.
  
  When opening a volume, the server might check the volume
  history table in the database to determine if the volume is
  already used. If a volume history table is very large, the
  server can spend an excessive amount of time searching it.
  Other sessions or processes can be delayed due to locking.
  To prevent this situation, regularly prune entries from the
  volume history table.
  
  You can define an administrative schedule for the
  DELETE VOLHISTORY command to delete volume history
  entries such as STGNEW, STGDELETE, and STGREUSE that are
  older than the oldest database backup needed to perform a
  point in time database restore.
  
  Consider deleting other types of entries if there are also
  many of them.
  
  The contents of the volume history file is created using the
  volume history table in the server database.
  
  
  Administrator's Guide:
  Incorporate the text into the existing topic "Saving the volume
  history file" in the chapter "Protecting and recovering your
  server."
  
  Performance Tuning Guide:
  Create a new topic "Monitoring the volume history file" in the
  chapter "Tivoli Storage Manager server performance tuning."
  
  
  Affected platforms:  AIX, HP-UX, Sun Solaris, Linux,
  and Windows.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

Applicable component levels