System logger stores log data on DASD in VSAM linear data sets when the log data in interim storage either reaches its installation defined threshold or fills. The VSAM linear data sets used for a log stream are called the log stream offload data sets. Both a DASD-only log stream and a coupling-facility log stream can have data in multiple offload data sets on DASD. System logger automatically allocates new ones for the log stream. During this offload data sets switch activity, System logger increments the sequence number (suffix qualifier) in the log stream data set name as new data sets are added for a particular log stream. See Naming conventions for the log stream and DASD data sets for information on using SMS.

IBM® suggests that you use System Managed Storage (SMS) to manage DASD log data sets. See Specifying SMS data set characteristics for DASD data sets for more information on using SMS.

System logger can use DFHSM or another product to migrate DASD log data sets. See Log stream data set migration and recall considerations for considerations on migrating and recalling log stream data sets.