Advanced Topics › Control and Checkpoint File Considerations › Control File Size Considerations

Control File Size Considerations

In a synchronized MIMplex, only the first one or two blocks of the control file are used. The largest usage of control file space usually occurs during MIMplex transition states, such as when a new CA MIM address space is joining an existing MIMplex or when a control file is being migrated. During these transition states, CA MIM may generate a large volume of transactions to communicate the current status of the resources managed by each component to the systems requiring this information.

Note: For more information, see Control File Blocks and the Global-Copy Process.

The CA MIM control file must be large enough to accommodate the number of transactions generated during these transition states. The amount of space required during these transition states depends on the components active in the MIMplex, and also may depend on workload.

• For CA MIA and CA MIC, a primary control file size of 10 MB is usually sufficient.
• For CA MII component, the space required during these transition periods depends on the number of concurrently held managed ENQ resources. This number varies widely by installation and can be a changeable value.

To help you determine the correct size of the control file for MIMplexes running CA MII, issue the following command to calculate the global copy space required based on the peak number of concurrently held ENQ resources since product startup:

DISPLAY GDIF CFSIZE

Note: For more information, see the Statement and Command Reference Guide.