You can enhance catalog performance by carefully selecting VSAM attributes when you define the catalog. Some catalog characteristics cannot be altered once the catalog is defined, so you should pay careful attention when selecting catalog characteristics.

Because the BCS of a catalog is a VSAM key-sequenced data set, you can enhance BCS performance by using the same considerations that you would use for similar key-sequenced data sets. For more information on performance considerations for VSAM data sets, see z/OS DFSMS Using Data Sets.

The following sections address VSAM attributes for performance and recommended selections as they apply to catalogs in non-RLS mode. These VSAM attributes are ignored for catalogs in RLS mode. All parameters discussed are used on the DEFINE USERCATALOG command.