Using the Metro Mirror heartbeat

This topic provides information about Metro Mirror heartbeat, including how to enable and disable the heartbeat.

Metro Mirror heartbeat
The heartbeat is a Metro Mirror function. When the Metro Mirror heartbeat is disabled, data consistency across multiple storage systems is not guaranteed if the Copy Services Manager management server cannot communicate with one or more storage systems. The problem occurs as a result of the Hardware Freeze Timeout Timer function within the storage system. If the controlling software loses connection to a storage system, the Metro Mirror relationships that it is controlling remains established and there is no way to freeze those pairs to create consistency across the multiple storage systems. When the freeze times out, dependent I/O is written to the target storage systems, which might corrupt data consistency. Freeze refers to a Metro Mirror (peer-to-peer remote copy [PPRC]) freeze function.
Enabling and disabling the Metro Mirror heartbeat
The Metro Mirror heartbeat guarantees data consistency across multiple storage systems when the Copy Services Manager management server cannot communicate with one or more storage systems. The Metro Mirror heartbeat is disabled by default.