Logging Considerations….

• Unavailable O/P Buffers
•  Write Threshold
  – Defaults 20, 400K
  – When/Why change this?
•  I/P Buffer Vs Archive Log Size
•  DASD SubSystem Performance
  – Device Placement
  – RAID??
•  Calculating Logload Value
  – (WriteNoWait/Time) * 20

Logging is the most critical function for DB2, because data integrity must be maintained. If DB2 cannot log, for any reason, the entire system will stop and wait until the problem is resolved. Unavailable O/P buffers is rarely a problem during the transaction processing day, but often becomes a factor during large batch update runs.
This should be monitored on a regular basis, and action taken if this threshold is hit. One of the more common problems than cause this, is poor DASD subsystem performance, especially for the devices that have the LOG datasets.