Both coupling facility and DASD-only log streams use DASD space for log data sets and staging data sets. All of the planning steps in this topic must be performed for either coupling facility or DASD-only log streams, unless otherwise noted.

System logger allocates VSAM linear data sets for the DASD log data sets and DASD staging data sets.

IBM® strongly recommends that these DASD data sets be SMS-managed.

System logger does not support the Guaranteed Space Option in SMS Storage Classes. Use of this option will cause system logger to only write to the first extent of any data set allocated in this manner.

System logger does allow VSAM data striping for DASD log data sets and DASD staging data sets.

Do not use a JCL data set retention period or expiration date to manage log data sets. See Managing log data: How much? For how long? for managing your log data sets.