IBM Support

IV97415: CAA:SLOW GOSSIP TRANSMISSION ON BOOT MAY CAUSE PARTIONED CLUSTERAPPLIES TO AIX 7200-00

A fix is available

Obtain the fix for this APAR.

Subscribe

You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • After rebooting, one of the cluster nodes was not able
to join  the cluster environment.
- lscluster from each node did not show the other node as
  UP.
- After system reboot, the syslog.caa log file showed
  a delay of over 2 minutes in getting the first
multicast
  gossip packet.
  When this delay occurs, the node creates its own
cluster
  ignoring the other node which is already up.
  This leads to a split-brain / partitioned cluster
  in the CAA environment.

Local fix

  • n/a

Problem summary

  • If a node is rebooted and, due to network issues, fails to
receive a gossip from other UP nodes within twice of
node_down_delay, could join by itself, causing a split-brain
(partitioned cluster).

Problem conclusion

  • There is a gate in which all initial clusterwide lock requests
should consider the count of nodes heartbeating to the
repository in addition to those gossiping over network.
There was a hole in the gate and the fix closes it.

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV97415
    • 

  • Reported component name
    AIX V7.2
    • 

  • Reported component ID
    5765CD200
    • 

  • Reported release
    720
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Submitted date
    2017-06-22
    • 

  • Closed date
    2017-06-22
    • 

  • Last modified date
    2017-09-25
    • 





    

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

    
IV97148
    

    • 

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

    • 



Fix information


    

  • Fixed component name
    AIX V7.2
    • 

  • Fixed component ID
    5765CD200
    • 



Applicable component levels


    

  • R720  PSY  U874043
       UP17/09/21  I  1000
    • 



PTF to Fileset Mapping








      
              
                            

              

              [{"Business Unit":{"code":"BU070","label":"IBM Infrastructure"},"Product":{"code":"SSVEF8","label":"AIX 7.2 Enterprise Edition"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"720","Edition":"","Line of Business":{"code":"LOB68","label":"Power HW"}},{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SG11S","label":"AIX 7.2 HIPERS, APARs and Fixes"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"720","Edition":"","Line of Business":{"code":"LOB08","label":"Cognitive Systems"}}]
              

                                                                    

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            10 September 2025
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
Page Feedback