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IV04295: AIX PCM MAY SEND I/O TO NON-OPTIMIZED PATHS WITH ALUA ENABLED APPLIES TO AIX 5300-12

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APAR status

  • Closed as program error.

Error description

  • With the introduction of V8 ONTAP firmware on the Netapp,
if
ALUA is enabled on the array, AIX PCM may wrongly
direct I/O to NON-OPTIMIZED paths. This can be
determined by observing I/O on the partner paths/
NON-OPTIMIZED paths.

Local fix

  • turn off ALUA on the array and use dotpaths to manage
path priorties and or back level the version of ONTAP
to version 7.xx

Problem summary

  • Even when ALUA is enabled, AIX PCM may send down IO thru
non-optimized paths instead of optimized paths. It can be
observed by monitoring IO on different paths.

Problem conclusion

  • The issue was the result of optimized port info getting wiped
out due to interference of simultaneous probing of ALUA on
different paths. Code in AIX PCM fixed so as to prevent such
interference.

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV04295
    • 

  • Reported component name
    AIX  5.3
    • 

  • Reported component ID
    5765G0300
    • 

  • Reported release
    530
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Submitted date
    2011-08-03
    • 

  • Closed date
    2011-08-03
    • 

  • Last modified date
    2013-04-07
    • 





    

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

    
IZ99315
    

    • 

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

    • 



Fix information


    

  • Fixed component name
    AIX  5.3
    • 

  • Fixed component ID
    5765G0300
    • 



Applicable component levels


    

  • R530  PSY  U844638
       UP11/10/10  I  1000
    • 



PTF to Fileset Mapping








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            07 April 2013
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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