Archive log data sets are dynamically allocated. When you install or reconfigure the PowerExchange Logger, you specify the data set name prefix, block size, unit name, and DASD sizes needed for allocation.

The emergency restart data sets (ERDS) contains approximately 1,000 entries for the archive log data sets. When the PowerExchange Logger reaches the last entry, it wraps to the beginning, overwriting the oldest entry.

Define dual archive logs to prevent potential data loss if one copy is corrupted or accidentally deleted.

Configure the Logger parameters so at least the first archive log copy is created on DASD. The second archive log copy can be placed on tape.

You can archive DASD archive logs to tape provided that the storage management system automatically restores them to DASD when they are dynamically allocated.

You can specify that your secondary archive log data sets be stored on a different device and device type from that used to store your primary archive log data sets. You can also specify different SMS classes for your primary and secondary archive logs.

If you archive data to tape, adjust the size of the log data sets so that each set contains the amount of space that can be stored on a tape volume. Doing so minimizes tape handling and volume mounts and maximizes the use of tape resources.

Because archive log data sets written to DASD cannot extend to another volume, make the primary space allocation (both quantity and block size) large enough to contain all of the data coming from the active log data sets. Allocate primary space with the PRIM_SPACE option of the DEFINE statement.

As each active log becomes full, the PowerExchange Logger offloads the log data to an archive log. If the rate of changes flowing into the Logger fills all of the active logs before the Logger finishes offloading their data to an archive, the Logger stops accepting changes for 2 minutes. During this pause, the Logger tries to finish its current archive log. The PowerExchange Logger continues in this mode until it completes offloading data to an archive or until you stop the PowerExchange Logger manually.

When the PowerExchange Logger abends because of data set out-of-space conditions, the action that the PowerExchange Logger takes depends on the abend code: