The catalog data space cache (CDSC) resides in a data space that you define with the COFVLFxx member of SYS1.PARMLIB. The CDSC uses the virtual lookaside facility (VLF), which can be started using the START VLF operator command. See Defining the Catalog Data Space Cache (COFVLFxx) for information on defining the CDSC.

You can add catalogs to the CDSC only by editing the COFVLFxx member to specify the catalogs, stopping VLF, then starting VLF. Because this releases the existing CDSC, catalog performance might be degraded for a while.

The CDSC can concurrently be used for any catalog that is not using the ISC. A single catalog cannot use both the CDSC and the ISC. Unlike the ISC, catalogs cached in the CDSC are not limited to a specific amount of storage. A catalog caches records until no space is left in the data space cache. Once the data space cache is full, the space occupied by the record least used is removed to make room for new records.

See Monitoring the Catalog Address Space for information on monitoring the performance of the CDSC.