Configuration options for FDBR regions

There can be one FDBR region for each IMS subsystem in the data sharing group. The FDBR region should be on a separate z/OS® system from the IMS that it tracks. This is to protect the FDBR region during a z/OS system failure on the system that contains the tracked IMS.

You can configure FDBR in several ways. The following figure shows FDBR regions placed with IMS subsystems. Each FDBR region tracks an IMS subsystem on a different z/OS system. This configuration has the advantage of low resource requirements.

In this configuration, if IMS1 fails, FDBR1 detects the failure and recovers any databases that IMS1 was using when it failed. If z/OS1 fails (with both IMS1 and FDBR4), FDBR1 recovers the database resources for IMS1, and FDBR4 can be established on another system until z/OS1 is restarted.
Figure 1. System configuration 1 for FDBR tracking of IMS subsystems
begin figure description. This figure illustrates 4 z/OS systems, each with an IMS and an FDBR region. end figure description.

The following figure shows all FDBR regions on a separate z/OS system from the tracked IMS subsystems. This configuration requires an additional hardware resource (the extra z/OS system). If a z/OS system failure occurs on z/OS1, z/OS2, or z/OS3, none of the FDBR regions are affected.

Figure 2. System configuration 2 for FDBR tracking of three IMS subsystems
begin figure description. This figure illustrates four z/OS systems, three of which have an IMS with the FDBR regions are on the fourth. end figure description.