z/OS includes a facility for managing system resource recovery, called resource recovery services (RRS). RRS is the sync-point manager, which coordinates the update and recovery of multiple protected resources. RRS controls how and when protected resources are committed by coordinating with the resource managers (such as IMS) that have registered with RRS.

RRS provides a system resource recovery platform such that applications that run on z/OS can have access to local and distributed resources and have system-coordinated recovery management of these resources. RRS support includes these features and services:

• A sync-point manager to coordinate the two-phase commit process⁹
• Implementation of the SAA® commit and backout callable services for use by application programs
• A mechanism to associate resources with an application instance
• Services for resource manager registration and participation in the two-phase commit process with RRS
• Services to allow resource managers to express interest in an application instance and be informed of commit and backout requests
• Services to enable resource managers to obtain system data to restore their resources to consistent state
• A communications resource manager (called APPC/PC for APPC/Protected Conversations) so that distributed applications can coordinate their recovery with participating local resource managers

Related Reading: For more information about how IMS uses RRS, see the Resource Recovery Services/MVS.