IT38381: After migrating to IBM MQ 9.2, a multi-instance queue manager fails over sooner in response to delays in log write operations

APAR status

• Closed as program error.

Error description

• MQ multi-instance queue manager running in MQ 9.2 fails over due
  to delay in log write for 20+ seconds whereas the QM running in
  MQ 9.1 could cope with log write delays up to 120 seconds by
  default.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of MQ multi-instance queue manager in MQ 9.2 / 9.2.x
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  The log write timeout in MQ 9.2 was previously set to 20 seconds
  and this caused the QM to trigger a failover to a multi-instance
  standby queue manager if there was a log write delay of 20
  seconds or more.
  

Problem conclusion

• MQ logic has been modified to change the default log write
  timeout to 60 seconds and with this the QM could cope with log
  write delays up to 120 seconds.
  
  As described in more detail in the MQ performance reports, slow
  log writes present a bottleneck to the queue manager's
  persistent/transacted message workload. Any such IO write delays
  should be investigated and remediated at the storage layer to
  avoid a resulting degredation of service to the queue manager.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.5
  v9.x CD    9.2.5
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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

  MQ BASE V9.2

• Fixed component ID

  5724H7281

Applicable component levels