IJ52262: FIX STARVATION OF PENDING WRITES IN CTDB QUEUES

APAR status

• Closed as program error.

Error description

• CTDB uses a queue to receive requests and send answers. However
  there was an issue that gave priority to the receiving side so,
  when a request was processed and the answer posted to the
  queue,if another incoming request arrived, it was served before
  sending the previous answer. On high traffic this can lead to
  CTDB long waits and starvation.
  

Local fix

Problem summary

• CTDB uses a queue to receive requests and send answers. However
  there was an issue that gave priority to the receiving side so,
  when a request was processed and the answer posted to the
  queue,if another incoming request arrived, it was served before
  sending the previous answer. On high traffic this can lead to
  CTDB long waits and starvation.
  

Problem conclusion

• This problem is fixed in 5.1.9.6
  To see all Spectrum Scale APARs and their respective
  Fix solutions refer to page: 
  https://public.dhe.ibm.com/storage/spectrumscale/spectrum_scale
  _apars.htmlBenefitsof the solution:Avoid lock contention scenari
  
  
  Work Around:
  None
  
  Problem trigger:
  High traffic and large number of accesses to contented file
  path.
  
  Symptom:
  Frequent CTDB recovery and crashes
  
  Platforms affected:
  ALL Operating System environments
  
  Functional Area affected:
  SMB
  
  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