IJ40845: READDIR PERFORMANCE ISSUES ON COS BACKEND

APAR status

• Closed as program error.

Error description

• Object readdir messages are not filtered if the multiple
  readdir operations for the same directory comes to the
  gateway node. This causes performance overhead and deadlocks.
  

Local fix

Problem summary

• Object readdir messages are not filtered if the multiple
  readdir operations for the same directory comes to the
  gateway node. This causes performance overhead and deadlocks.
  

Problem conclusion

• This problem is fixed in 5.1.4 PTF 1
  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:
  Fixed the code to filter readdir messages so that
  redundant and expensive List/Lisv2 operations to
  the COS are avoided.
  
  Work around: None
  Problem trigger:
  AFM+COS caching mode with multiple readdirs
  on the same uncached directory.
  Symptom:  Long Waiters/Deadlock
  Platforms affected:  All Linux OS environments
  Functional Area affected:  AFM
  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