IT22009: STANDBY CRASHES IF MIRROR LOG PATH IS CHANGED AND DATABASE IS NOT REACTIVATED AFTERWARDS.

Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• The standby will crash if the mirror log path is changed to NULL
  without reactivating the database on standby and is unmounted
  afterwards.
  
  The issue is seen when -
  1. Setup HADR pair with mirror log path enabled
  2. Constantly running workload on primary
  3. Update the mirror log path to NULL on standby and do not
  reactivate the standby at all
  4. Rename the mirror log path to a different name so standby
  would not find it.
  5. Search for following db2diag.log entry. The message is the
  key as it adds S0000196.LOG to mirfhdr.dualLogError[]. This
  would make sqlpgCheckFileIsGood() return false to the mirror
  path copy.
  (After mirror log path gets renamed, the first file that standby
  writes to would trigger this message.
  The subsequent logs would not trigger this.)
  
  2016-11-18-11.40.48.644243-300 E4741258E985          LEVEL:
  Error
  PID     : 26632                TID : 46913273456960  KTID :
  28761
  PROC    : db2sysc
  INSTANCE: db2inst1              NODE : 000            DB   :
  SAMPLE
  HOSTNAME: hostabc
  EDUID   : 124                  EDUNAME: db2hadrs.0.0 (SAMPLE)
  FUNCTION: DB2 UDB, data protection services, sqlpgStartMfhEntry,
  probe:7520
  MESSAGE : ADM1839W  An error occurred while DB2 was writing log
  data to log
            file "S0000196.LOG" on path
  
  "/home/hostabc/db2inst1/mirrorpath/NODE0000/LOGSTREAM0000/".
  The
            log file is still available on log path
  
  "/home/hostabc/db2inst1/db2inst1//NODE0000/SQL00001/LOGSTREAM
            0000/".  DB2 will attempt to use both paths for
  subsequent log files.
            In the meantime, check that the specified log path in
  which the error
            occurred exists and is accessible.  Also check that
  there is space
            available in the file system.
  
  6. Rename the mirror log path back.
  7. The rename would succeed on active path and failed on mirror
  path. (For example, renamed 196 to 200)
  8. When standby tries to write 200.LOG, it would crash.
  

Local fix

• Reactivating the database after log mirror path is changed.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Db2 11.1 Mod 3 Fix Pack 3 or higher               *
  ****************************************************************
  

Problem conclusion

• First fixed in Db2 11.1 Mod 3 Fix Pack 3
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IT18553

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

     UP