Shared Disk Facility (CMS TMCs Only) › Components › Implementing the Shared Disk Facility

Implementing the Shared Disk Facility

To implement read/write sharing of CMS minidisks, allocate a control area beyond the logical end of the CMS minidisk. The CA VM:Tape VMTSDF utility assigns a lock in this control area to each participating system. CA VM:Tape uses this control area to synchronize access to the minidisk by setting and resetting lock records.

To implement the CA VM:Tape Shared Disk facility, follow these steps:

1. Ensure all CA VM:Tape machines have identical MDISK entries for the TMC and Audit minidisks because each CA VM:Tape service virtual machine is executing on a separate real CPU.
2. Format the control area on the TMC and Audit minidisks using the VMTSDF utility from one of the CA VM:Tape user IDs.

   Note: For instructions about formatting the control area, see VMTSDF Utility.

3. In the CA VM:Tape configuration file of each CA VM:Tape system, specify a SYSNAME record that identifies the local CA VM:Tape system’s name and enables execution of shared disk logic.

   Note: For more information about the SYSNAME record, see SYSNAME Record.

4. In the CA VM:Tape configuration file of each CA VM:Tape system, specify a VMTAPE configuration file record indicating the CA VM:Tape user IDs that make up the shared environment.

   Note: For more information about the VMTAPE record, see VMTAPE Record.