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Managing log files
If you are using circular logging, ensure that there is sufficient space to hold the log files when you configure your system (see Log defaults for WebSphere MQ and Queue manager logs). The amount of disk space used by the log does not increase beyond the configured size, including space for secondary files to be created when required.
If you are using a linear log, the log files are added continually as data is logged, and the amount of disk space used increases with time. If the rate of data being logged is high, disk space is consumed rapidly by new log files.
Over time, the older log files for a linear log are no longer needed to restart the queue manager or to perform media recovery of any damaged objects. The following are methods for determining which log files are still required:
- Logger event messages
- When enabled, logger event messages are generated when queue managers starts writing log records to a new log file. The contents of logger event messages specify the log files that are still required for queue manager restart, and media recovery. For more information on logger event messages, see WebSphere MQ Monitoring
- Queue manager status
- Executing the MQSC command, DISPLAY QMSTATUS, or the PCF command, Inquire Queue Manager Status, returns queue manager information, including details of the required log files. For more information on MQSC commands, see the WebSphere MQ Script (MQSC) Command Reference manual, and for information on PCF commands, see the WebSphere MQ Programmable Command Formats and Administration Interface manual.
- Queue manager messages
- Periodically, the queue manager issues a pair of messages to indicate which of the log files are needed:
- Message AMQ7467 gives the name of the oldest log file needed to restart the queue manager. This log file and all newer log files must be available during queue manager restart.
- Message AMQ7468 gives the name of the oldest log file needed for media recovery.
Only log files required for queue manager restart, active log files, need to be online. Inactive log files can be copied to an archive medium such as tape for disaster recovery, and removed from the log directory. Inactive log files that are not required for media recovery can be considered as superfluous log files. We can delete superfluous log files if they are no longer of interest to your operation.
If any log file that is needed cannot be found, operator message AMQ6767 is issued. Make the log file, and all subsequent log files, available to the queue manager and retry the operation.
When performing media recovery, all the required log files must be available in the log file directory at the same time. Make sure that you take regular media images of any objects you might wish to recover to avoid running out of disk space to hold all the required log files.
Messages AMQ7467 and AMQ7468 can also be issued at the time of running the rcdmqimg command. For more information about this command, see rcdmqimg (record media image).
Parent topic:
Managing logs
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