# Activating Mainframe Logger

The member "TIBSLOG", located in the `USERHLQ.PARM` PDS, specifies the names of the streams and other parameters for the mainframe logger.

Use the TIBSLOG member and change its content according to the changes in your environment. If you change the member name, change the Substation ES and HUB parameters pointing to TIBSLOG member. It's a common member that can be used by multiple systems. TIBCO recommends the following approach:

For Substation ES:

- System Startup Parameters (SXSSSP$1) member has a keyword SYSLOG-MEM that points to the logging parameters

For Mainframe HUB:

- Startup Parameters (SXXHUB or SXXHUBSA) member has a keyword SYSLOG-MEM that points to the logging parameters

The mainframe logger functions are turned off, if the keyword SYSLOG-MEM is not specified.

Note: If you chose to write records to the logger streams, then it's mandatory that you start a Mainframe HUB in the same LPAR where the application is executing, specifying the logger streams for any applications running in CICS, IMS, batch or to use the log stream viewer.

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