Communication Methods › Allocating DASD Control Files › Where to Locate Your DASD Control Files

Where to Locate Your DASD Control Files

Allocate DASD control files on devices that are accessible to all systems in the installation. Follow these guidelines when deciding where to locate your control files:

• The volume that you choose must not be the target of frequent reserve requests from any other products.
• A CA MIM control file should never reside on the same pack as a:
  • StorageTek HSM control file.
  • CA 1 Tape Management Catalog (TMC).
  • Shared RACF data set.
• Files must reside on a low-contention volume.
• Do not allocate files on a volume containing the spool, the JES checkpoint data set, a catalog, or your page or swap data sets.
• If possible, allocate files in a location that requires minimal (or no) head movement to access.

Allocate backup control files on a different device from the one on which the primary control file resides. A good practice is to allocate backup control files on devices that use a different channel and controller.

We recommend that you allocate a minimum of ten cylinders per file on a cylinder boundary. The cylinders must be contiguous; that is, they must be contained in a single extent.