Recovering systems in an IMSplex

The recovery of an IMS system can be managed by the Extended Recovery Facility (XRF). An IMS Fast Database Recovery region (FDBR) can also be used for recovery purposes.

XRF

Performs takeover on a system-by-system basis; XRF relies on the same physical databases and many of the same physical resources as the active IMS system.

XRF can be used in an IMSplex in the same way that it is used on a local system. The XRF alternate system needs to have a unique IMSID in the IMSplex, be defined in the IMSplex and have access to the CSL. An SCI must reside on the z/OS® image where the XRF alternate resides. You cannot use XRF to recover an entire IMSplex, but you can use XRF to recover an individual IMS in an IMSplex.

An IMS Database Control (DBCTL) warm standby region and an IMS Fast Database Recovery region (FDBR) can also be used for recovery purposes.

FDBR

An FDBR region monitors an IMS subsystem and can automatically recover database resources (shared databases and areas) if that IMS subsystem fails.

DBCTL standby

While one DBCTL subsystem is active, you can start another DBCTL subsystem as a standby alternate. This alternate subsystem does not track the active subsystem (as it would in an XRF complex), but is a fully initialized IMS DBCTL subsystem that is waiting for a restart command.

An IMSplex can include XRF, FDBR, and DBCTL standby regions.