IJ54979: TWICE THE FILE SIZE AMOUNT OF DATA IS SENT BETWEEN CLUSTERS

APAR status

• Closed as program error.

Error description

• With afmFastCreate enabled, if the Create that tries to push the
  initial chunk of data fails to complete and gets requeued, then
  the requeued Create is replaying all data when it retries.And
  later there are a couple of Write messages that starting from
  offset where Create initially went inflight that is also played.
  Totaling to almost twice the amount of data of the file size to
  be replicated.
  

Local fix

• Set a higher value of afmAsyncDelay to push replication as far
  as the file is being written.
  

Problem summary

• With afmFastCreate enabled, if the Create that tries to push the
  initial chunk of data fails to complete and gets requeued, then
  the requeued Create is replaying all data when it retries.And
  later there are a couple of Write messages that starting from
  offset where Create initially went inflight that is also played.
  Totaling to almost twice the amount of data of the file size to
  be replicated.
  

Problem conclusion

• This problem is fixed in 5.1.9.10
  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:
  Check if the file is open anywhere (in line with Object), for
  afmFastCreate - Create messages. If file is open - don't 
  replicate until closed. This also helps to gain a bit of
  performance with afmFastCreate.
  
  Work around:
  Set a higher value of afmAsyncDelay to push replication as far
  as the file is being written.
  
  Problem trigger:
  afmFastCreate replication failing initially because of lock or
  network error and later replication being tried again.
  
  Symptom:
  Unexpected Behaviour
  
  Platforms affected:
  All Linux OS Environments (AFM Gateway nodes)
  
  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