IBM Support

IT43349: Delay in IBM MQ 9.2/9.3 multi-instance queue manager failover/switchover

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APAR status

  • Closed as program error.

Error description

  • IBM MQ multi-instance queue manager failover/switchover might be
slow in IBM MQ 9.2/9.3 when comparing with IBM MQ versions older
than 9.2.

Local fix

  • 



Problem summary


    

  • ****************************************************************
USERS AFFECTED:
Users using IBM MQ multi-instance queue manager with some NFS
file systems which do not support timely lock notification to
NFS clients.


Platforms affected:
MultiPlatform

****************************************************************
PROBLEM DESCRIPTION:
IBM MQ 9.2 and 9.3 used blocking file locks whereas IBM MQ 9.1
and older IBM MQ versions use non-blocking locks to implement
IBM MQ multi-instance queue manager failover/switchover. When
the active instance ends the standby instance acquires the lock
and becomes active. However in some NFS implementations, the NFS
server may not immediately notify the standby instance about the
release of the blocking lock by the active instance if the
standby instance has been waiting for the lock for a longer
period (e.g. 30 seconds). This caused a delay in queue manager
failover/switchover.

    



Problem conclusion


    

  • The IBM MQ code has been modified to use non-blocking locks for
multi-instance queue manager failover/switchover.

---------------------------------------------------------------
The fix is targeted for delivery in the following PTFs:

Version    Maintenance Level
v9.2 LTS   9.2.0.15
v9.3 LTS   9.3.0.10
v9.x CD    9.3.4

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 number
    IT43349
    • 

  • Reported component name
    MQ BASE V9.2
    • 

  • Reported component ID
    5724H7281
    • 

  • Reported release
    920
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2023-03-14
    • 

  • Closed date
    2023-05-19
    • 

  • Last modified date
    2023-05-19
    • 





    

  • 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


    








      
              
                            

              

              [{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"920","Line of Business":{"code":"LOB45","label":"Automation"}}]
              

                          

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            20 May 2023
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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