How dual archive logging works

Each log control interval (CI) that is retrieved from the active log is written to two archive log data sets. The log records that are contained on a pair of dual archive log data sets are identical, but ends-of-volumes are not synchronized for multivolume data sets.

Archiving to disk offers faster recoverability but is more expensive than archiving to tape. If you use dual logging, on installation panel DSNTIPA enables you to specify that the primary copy of the archive log go to disk and the secondary copy go to tape.

Dual archive logging increases recovery speed without using as much disk. The second tape is intended as a backup, or it can be sent to a remote site in preparation for disaster recovery. To make recovering from the COPY2 archive tape faster at the remote site, use the installation parameter ARC2FRST to specify that COPY2 archive log should be read first. Otherwise, Db2 always attempts to read the primary copy of the archive log data set first.