IT04946: IN CERTAIN CIRCUMSTANCES THE BFDEREFQUEUETHREAD THREAD CAN HOLD AN EXCESSIVE NUMBER OF LOCKS.

7.1.5.000-TIV-TSMSRV-AIX
7.1.5.000-TIV-TSMSRV-HP-UX
7.1.5.000-TIV-TSMSRV-Linuxppc64
7.1.5.000-TIV-TSMSRV-Linuxs390x
7.1.5.000-TIV-TSMSRV-Linuxx86_64
7.1.5.000-TIV-TSMSRV-SolarisSPARC
7.1.5.000-TIV-TSMSRV-WIN
IBM Spectrum Protect Server V7.1 Fix Pack 5 (7.1.5.000) Downloads

APAR status

• Closed as program error.

Error description

• In certain circumstances, especially when a large number of
  files have been deleted, for example through expiration, the
  bfDerefQueueThread thread can hold an excessive number of locks.
  This can then cause database lock escalations.
  
  
  When lock escalations are occurring, there will be a noticeable
  slow down of the server performance. It is also likely that the
  active log space will begin filling as database transaction
  processing takes longer. This could cause a server outage if the
  log space fills.
  
  To see if you are affected by this problem, verify that there
  are 'LLM-memory low' messages and lock escalations messages in
  the db2diag.log file. For example:
  
  
  Locking memory management: LLM-memory low.
  Escalation threshold activated.
  LLM-lock list size = 148650000
  LLM-lock list available = 1936
  
  
  ADM5501I  DB2 is performing lock escalation. The affected
  application is named "dsmserv", and is associated with the
  workload name "SYSDEFAULTUSERWORKLOAD" and application ID
  "*LOCAL.tsminst1.140929162329"  at member "0". The total
  number of locks currently held is "3733", and the target
  number of locks to hold is "1866".
  

Local fix

• Increase the DB2 LOCKLIST for the database.
  
  To find an appropriate value by which to increase the LOCKLIST,
  first run the commands below to find the count of dereferenced
  chunks per node/fsid in the BF_DEREFERENCED_CHUNKS table:
  
  $ db2 connect to tsmdb1
  $ db2 "select nodeid, fsid, count(*) from
  tsmdb1.BF_DEREFERENCED_CHUNKS group by nodeid, fsid" >
  bfdc_count.txt
  
  In the 'bfdc_count.txt' output file, find the largest value in
  the third column, which represents the number of dereferenced
  chunks for a node/fsid combination.
  
  Say for example that '40,000,000' is the largest number in that
  column. Also assume that each lock consumes 128 bytes of memory
  and that the LOCKLIST value represents the number of 4096-byte
  pages. Increase the LOCKLIST by a number sufficient to handle
  '40,000,000' by calculating as below. In this case you want to
  increase the LOCKLIST by 1,250,000-
  
  
  
  40000000 * 128 bytes / 4096 bytes = 1250000
  
  
  So if your current LOCKLIST is set to '500000', increase that
  number by 1250000 by setting a new LOCKLIST of 1750000.
  
  For steps to change the lock list in the database configuration,
  refer to the documentation at the link below-
  
  
  http://www-01.ibm.com/support/docview.wss?uid=swg21430874
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Tivoli Storage Manager server users.                     *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See error description.                                       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply fixing level when available. This problem is currently *
  * projected to be fixed in level 7.1.5. Note that this is      *
  * subject to change at the discretion of IBM.                  *
  ****************************************************************
  

Problem conclusion

• This problem was fixed.
  Affected platforms:  AIX, HP-UX, 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

• Fixed component name

  TSM SERVER

• Fixed component ID

  5698ISMSV

Applicable component levels