When you are deciding which coupling facility structures to associate with each coupling facility log stream, you can plan it so that system logger can easily recover coupling facility data in the case of a system failure. This step applies to coupling facility log streams only.

When a system that has a system logger application fails, system logger tries to safeguard all the coupling facility log data for the failed system either by offloading it to DASD log data sets so that it is on a persistent media or by ensuring that the log data is secure in a persistent duplex-mode list structure. This recovery processing is done by a peer connector, which is another system in the sysplex with a connection to the same coupling facility structure as the failing system. In general, when you set up your logging configuration, make sure that each log stream structure is accessed by more than one system. Note that a peer connector need only be connected to the same coupling facility structure, not the same log stream.

If there is no peer connection available to perform recovery for a failed system, recovery is delayed until either the failing system re-IPLs or another system connects to a log stream in the same coupling facility structure to which the failing system was connected. In general, however, the log stream data you need will be available when you need it: when a system reconnects or connects to a log stream that the failed system was connected to in order to write or retrieve data. Recovery will be performed when that peer connector connects to the log stream.