Just to clarify a few points from this thread: The CFRM policy should specify INITSIZE for a structure only when that structure supports alter. It's not meaningful otherwise.
The reason for the recommendation that SIZE should never be more than 1.5 - 2 times INITSIZE is that when the CF initially allocates a structure, it must provide sufficient internal control objects to support the structure's eventual maximum size. If SIZE is excessive relative to INITSIZE, it may be impossible to allocate the structure at size INITSIZE and still provide those internal control objects. Allocation may fail entirely, or it may create a structure with so much of its storage consumed by internal controls that it provides insufficient objects (entries, elements, etc.) for application use. Only DB2 GBP structures exploit user-managed duplexing. DB2 (IRLM) lock structures and DB2 list structures use system-managed duplexing. CFSizer and the SIZER utility are two different things, both available at the CFSizer web site (http://www.ibm.com/systems/support/z/cfsizer/). The SIZER utility is the tool of choice for migrations of the type described by the original post. It collects information about attributes and object counts for all currently allocated structures, and determines what size would be required to support the same attributes and counts in all CFs connected to the system where the utility is being run. It is useful when you are satisfied that the currently allocated structures are adequately sized for the existing workload. If you wish to verify that a structure is adequately sized, or if you're introducing a new workload type or changing an existing workload, that's when you use CFSizer. CFSizer requires you to provide input describing the application workload (peak ENQ count, message arrival rate and retention time, data base size, etc., specific to the application) and returns a size estimate based on that workload description. As noted in a previous append, it deliberately produces generous size estimates, because an undersized structure can cause serious problems while it's practically impossible to go wrong by moderately over-sizing a structure (assuming you don't exceed the CF's available storage). Bill Neiman IBM Parallel Sysplex development ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
