IJ39112: ENABLE FAST_BUFF_SCAN ON AIX

APAR status

• Closed as program error.

Error description

• Multiple NFS threads were doing 8K writes with sync
  request
  to commit data disk. This leads to mutex contention as we
  have many threads trying perform sync on the same file.
  To overcome this issue FAST_BUFF_SCAN should be enabled
  on
  AIX.
  

Local fix

• Reduce number of worker threads to something much smaller
  in order to reduce mutex contention.
  

Problem summary

• Mutex contention could lead to slow write performance
  on AIX when there are multiple threads trying to
  flush the same file that contain many blocks at same time.
  

Problem conclusion

• This problem is fixed in 5.1.2 PTF 6
  To see all Spectrum Scale APARs and
  their respective fix solutions refer to page
  https://public.dhe.ibm.com/storage/spectrumscale/spectrum_scale_
  apars.html
  
  
  Benefits of the solution:
  Better write performance on AIX
  
  Work Around:  None
  Problem trigger:
  Multiple threads invoking sync on the same
  file at the same time.
  Symptom:
  Performance Impact/Degradation
  Platforms affected:
  AIX/Power only
  Windows/x86_64 only
  Functional Area affected:
  All Scale Users
  Customer Impact:
  High Importance
  

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

  SPEC SCALE STD

• Fixed component ID

  5737F33AP

Applicable component levels