Determining the Size of Each Coupling Facility Structure
Your installation may decide to place the APPC/MVS log stream in
its own coupling facility list structure, or in a list structure containing
multiple log streams with the same attributes. In either case, as
you gather information about the coupling facility structure, and
the log streams that map to the structure, note the following APPC-specific
information related to parameters in the LOGR policy:
- AVGBUFSIZE
- The APPC/MVS log stream contains one log block for both of the
following:
- Each local/partner LU pair that has established sessions with protected conversations
- Each LU pair, if any, that has outstanding resynchronization work.
Each log block is the same size: 248 bytes. Use 248 as the value for the average size of APPC/MVS log blocks.
- MAXBUFSIZE
- APPC/MVS requires a buffer size of at least 65276 bytes. If you use a MAXBUFSIZE value that is less than 65276, APPC/MVS issues message ATB209I and does not allow APPC/MVS LUs to handle any protected conversations, until the buffer size is corrected and the LUs restarted.
- ResidencyTime
- You may use a relatively low value for residency time, because APPC/MVS writes to the log stream infrequently.