IBM Support

IV14654: DNLC THRASHING ON LARGE MEMORY SYSTEM WITH HEAVY NFS ACTIVITY APPLIES TO AIX 7100-00

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

  • The dnlc is used to cache directory entries. This
improves
performance significantly for directory operations such
as
ls.

A system with large memory (250GB or more) may experience
dnlc thrashing with high nfs activity. This will cause
nfs
performance to drop significantly and some operation on
nfs
mounts such as ls will become very slow.

Depending on the nfs activity the system may get into
this
state in a matter of days or weeks. In the case where
this
problem was reported the systems became unsable after 2
weeks
of uptime.

Local fix

  • Reboot the system to empty the dnlc cache.

Problem summary

  • Customer applicaitons will experience slow performance
issues with NFS

Problem conclusion

  • In nfs3_readdir(), remove code that purges the cache a second
time, since this leads to performance degradation.

Temporary fix

  • 



Comments


    

  • 



APAR Information




    

  • APAR number
    IV14654
    • 

  • Reported component name
    AIX V7.1
    • 

  • Reported component ID
    5765H4000
    • 

  • Reported release
    710
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Submitted date
    2012-02-01
    • 

  • Closed date
    2012-02-01
    • 

  • Last modified date
    2013-02-27
    • 





    

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

    
IV01612
    

    • 

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

    • 



Fix information


    

  • Fixed component name
    AIX V7.1
    • 

  • Fixed component ID
    5765H4000
    • 



Applicable component levels


    

  • R710  PSY  U846542
       UP12/03/30  I  1000
    • 



PTF to Fileset Mapping








      
              
                            

              

              [{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SSMV87","label":"AIX 6.1 Enterprise Edition"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"710","Edition":"","Line of Business":{"code":"LOB08","label":"Cognitive Systems"}},{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSMVAX","label":"AIX Express Edition"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"710","Edition":"","Line of Business":{"code":"LOB08","label":"Cognitive Systems"}},{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG11R","label":"AIX 7.1 HIPERS, APARs and Fixes"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"710","Edition":"","Line of Business":{"code":"","label":""}}]
              

                                                                    

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            27 February 2013
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
Page Feedback