Operlog Help

System logger is a set of services that allows an application to write, browse and delete log data. You can use system logger services to merge data from multiple instances of an application, including merging data from different systems across a sysplex. It uses list structures to hold the logstream data from exploiters of the system logger.

OPERLOG

The operations log (OPERLOG) is a log stream that uses the system logger to record and merge communications about programs and system functions from each system in a sysplex. Only the systems in a sysplex that have specified and activated the operations log will have their records sent to OPERLOG.

The operations log is operationally independent of the system log. An installation can chose to run with either or both of the logs.

Before you can begin using the operations log, you must define a log stream using the system logger services.

It's in the LOGR policy that keywords such as MAXBUFFSIZE, AVGBUFFSIZE, LOGSNUM, etc. are defined. To simplify the tool's interface, a design decision was made to externalize only those fields that could not default to a reasonable value. As such, the following defaults are used for sizing a log structure when you click the Size Structure button:

• MAXBUFFSIZE - specifies the size, in bytes, of the largest log block that can be written to log streams. This value must be between 1 and 65532. The default for OPERLOG is 4096.

• AVGBUFFSIZE - specifies the average size in bytes of log blocks written to all log streams. IBM recommends a value of 512. The logger uses the average buffer size to control the entry to element ratio.

• LOGSNUM - specifies the number of log streams allocated to a list structure. logsnum must be a value from 0 to 512. This tool defaults to 1.

• LOWOFFLOAD - specifies the point, in percent value of space consumed, where logger will stop offloading coupling facility log data to the DASD log data sets for this log stream. This defaults to 0.

• HIGHOFFLOAD - specifies the point, in percent value of space consumed, where logger will begin offloading coupling facility log data to the DASD log data sets for this log stream. This defaults to 80.

• RESIDENCY TIME - Desired residency time for log data in the coupling facility structure (i.e. the amount of time you want a log block to stay in the CF between the time it is written to the CF and being offloaded to DASD). This defaults to 10 seconds.

Writes per Second

The number of log blocks written to the log stream per second from all systems.
For OPERLOG, you can calculate projected writes per second using current SYSLOGS (choose a peak or high usage time of day). The IBM recommendation for calculating writes per second is over an interval of 2000 messages, calculated for each participating system.