WebSphere MQ commands, QUIESCE MODE of ARCHIVE LOG" /> Archiving logs with the ARCHIVE LOG command

 

Archiving logs with the ARCHIVE LOG command

An authorized operator can archive the current WebSphere MQ active log data sets whenever required using the ARCHIVE LOG command.

When you issue the ARCHIVE LOG command, WebSphere MQ truncates the current active log data sets, then runs an asynchronous off-load, and updates the BSDS with a record of the off-load.

The ARCHIVE LOG command has a MODE(QUIESCE) option. With this option, WebSphere MQ jobs and users are quiesced after a commit point, and the resulting point of consistency is captured in the current active log before it is off-loaded.

Consider using the MODE(QUIESCE) option when planning a backup strategy for off site recovery. It creates a system-wide point of consistency, which minimizes the number of data inconsistencies when the archive log is used with the most current backup page set copy during recovery. For example: 

  ARCHIVE LOG MODE(QUIESCE)

If you issue the ARCHIVE LOG command without specifying a TIME parameter, the quiesce time period defaults to the value of the QUIESCE parameter of the CSQ6ARVP macro. If the time required for the ARCHIVE LOG MODE(QUIESCE) to complete is less than the time specified, the command completes successfully; otherwise, the command fails when the time period expires. We can specify the time period explicitly by using the TIME option, for example: 

   ARCHIVE LOG MODE(QUIESCE) TIME(60)

This command specifies a quiesce period of up to 60 seconds before ARCHIVE LOG processing occurs.

Attention:
Using the TIME option when time is critical can significantly disrupt WebSphere MQ availability for all jobs and users that use WebSphere MQ resources.

By default, the command is processed asynchronously from the time you submit the command. (To process the command synchronously with other WebSphere MQ commands use the WAIT(YES) option with QUIESCE, but be aware that the z/OS console is locked from WebSphere MQ command input for the entire QUIESCE period.)

During the quiesce period:

  • Jobs and users on the queue manager are allowed to go through commit processing, but are suspended if they try to update any WebSphere MQ resource after the commit.

  • Jobs and users that only read data can be affected, since they might be waiting for locks held by jobs or users that were suspended.

  • New tasks can start, but they cannot update data.

The output from the DISPLAY LOG command uses the message CSQV400I to indicate that a quiesce is in effect. For example: 

  CSQJ322I +CSQ1 DISPLAY LOG report ...
  Parameter   Initial value          SET value
  ----------- ---------------------- ----------------------
  INBUFF      60
  OUTBUFF     4000
  MAXRTU      2
  MAXARCH     2
  TWOACTV     YES
  TWOARCH     YES
  TWOBSDS     YES
  OFFLOAD     YES
  WRTHRSH     20
  DEALLCT     0
  End of LOG report
  CSQJ370I +CSQ1 LOG status report ...
  Copy %Full DSName
   1     68  VICY.CSQ1.LOGCOPY1.DS01
   2     68  VICY.CSQ1.LOGCOPY2.DS01
  Restarted at 2005-02-24 09:49:30 using RBA=00000891B000
  Latest RBA=00000891CCF8
  Offload task is AVAILABLE
  Full logs to offload - 0 of 4
  CSQV400I +CSQ1 ARCHIVE LOG QUIESCE CURRENTLY ACTIVE
  CSQ9022I +CSQ1 CSQJC001 ' DISPLAY LOG' NORMAL COMPLETION

When all updates are quiesced, the quiesce history record in the BSDS is updated with the date and time that the active log data sets were truncated, and with the last-written RBA in the current active log data sets. WebSphere MQ truncates the current active log data sets, switches to the next available active log data sets, and issues message CSQJ311E stating that off-load started.

If updates cannot be quiesced before the quiesce period expires, WebSphere MQ issues message CSQJ317I, and ARCHIVE LOG processing terminates. The current active log data sets are not truncated, nor switched to the next available log data sets, and off-load is not started.

Whether the quiesce was successful or not, all suspended users and jobs are then resumed, and WebSphere MQ issues message CSQJ312I, stating that the quiesce is ended and update activity is resumed.

If ARCHIVE LOG is issued when the current active log is the last available active log data set, the command is not processed, and WebSphere MQ issues the following message: 

  CSQJ319I - csect-name CURRENT ACTIVE LOG DATA SET IS THE LAST
             AVAILABLE ACTIVE LOG DATA SET.  ARCHIVE LOG PROCESSING
             WILL BE TERMINATED

If ARCHIVE LOG is issued when another ARCHIVE LOG command is already in progress, the new command is not processed, and WebSphere MQ issues the following message: 

  CSQJ318I - ARCHIVE LOG COMMAND ALREADY IN PROGRESS

For information about the syntax of the ARCHIVE LOG command, see the WebSphere MQ Script (MQSC) Command Reference manual. For information about the messages issued during archiving, see the WebSphere MQ for z/OS Messages and Codes manual.