The archive failover log is used by the server if the archive log directory runs out of space.
Specifying an archive failover log directory is optional, but it can prevent problems that occur if the archive log runs out of space. If both the archive log directory and the drive or file system where the archive failover log directory is located become full, the data remains in the active log directory. This condition can cause the active log to fill up, which causes the server to halt. If you use an archive failover log directory, place the archive log directory and the archive failover log directory on different physical drives.
By monitoring the usage of the archive failover log, you can determine whether additional space is needed for the archive log. The goal is to minimize the need to use the archive failover log by ensuring that the archive log has adequate space.
The locations of the archive log and the archive failover log are set during initial configuration. If you use the DSMSERV LOADFORMAT utility instead of the wizard to configure the server, you specify the ARCHLOGDIRECTORY parameter for the archive log directory. In addition, you specify the ARCHFAILOVERLOGDIRECTORY parameter for the archive failover log directory. If the archive failover log is not created at initial configuration, you can create it by specifying the ARCHFAILOVERLOGDIRECTORY option in the server options file.