Operating System Software User Manual

between SystemB and SystemA, and in asynchronous periodic mode from SystemB to SystemC,
as shown in Figure 25 (page 73).
Figure 25 SystemA Becomes the Secondary-Reverse System
To restore normal operation, the setrcopygroup restore command is issued. SystemA becomes
the primary system; SystemB becomes the secondary system, and SystemC becomes the secondary
backup system. The backup link between SystemB and SystemC is once again inactive, because
the system is running normally (see Figure 22 (page 71)).
SystemA-to-SystemC Failover in SLD Remote-Copy Configuration
When an individual remote-copy volume group in SystemA fails (see Figure 23 (page 72), and
the administrator decides to fail over to SystemC rather than to SystemB, SystemB immediately
becomes the primary-reverse system and sends the latest update to SystemC, as shown in
Figure 26 (page 74).
Failover and Failback Behavior of Individual Remote-Copy Groups in SLD Configuration 73