Friday, March 16, 2012

Red Alert : Potential data loss when executing data recovery in a DB2 10 (NFM) Data Sharing environment

Here's a new Red Alert:

PTF UK76697 (APAR PM51093) is required for DB2 10 for z/OS NFM (New Function Mode) customers executing data recovery in a Data Sharing environment


IBM has become aware of potential data loss when executing data recovery in a DB2 10 Data Sharing environment.

The problem is related to Fast Log Apply processing when LRSN values are used for log record sequencing and may result in some log records not being processed when duplicate LRSN values are encountered. This situation applies to the RECOVER and RESTORE SYSTEM utilities and LPL and GRECP recovery. The REORG utility and DB2 restart processing are not exposed to this issue.

Possible symptoms include ABEND04E RC00C90102 DSNIBHRE:0C22 accompanied by MSGDSNI012I PAGE LOGICALLY BROKEN or other consistency errors during log apply. Other abends or errors may be encountered following log apply processing, including errors reported by CHECK INDEX or CHECK DATA.

Customers may validate their data by using CHECK INDEX or CHECK DATA utilities and any issues should be reported to IBM Software Support to determine root cause.

Recommended Actions:

It is recommended that all DB2 10 for z/OS data sharing customers apply PTF UK76697 as soon as possible. Customers planning to migrate to DB2 10 NFM should ensure that UK76697 is applied before they do so. The corrective maintenance can be applied incrementally across members of a data sharing group. A group wide restart is not required.

Fast Log Apply processing may be disabled to prevent further exposure to this problem before UK76697 can be applied. The process for doing so is as follows, and should be repeated for each subsystem:

  1. Edit macro DSN6SPRC in the SDSNMACS library.
  2. Change &SPRMFLB SETC '10' to &SPRMFLB SETC '0'.
  3. Run job DSNTIJUZ to reassemble and relink the new zparm.
  4. Recycle DB2 to load the new zparm.

Refer to the cover letter for UK76697 for further details regarding this issue.

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