Utilities › TMSINIT Utility—Activate, Deactivate CA 1 › Realtime Expiration

Realtime Expiration

CA 1 provides an optional feature known as Realtime Expiration. This enables you to apply the expiration dates defined in the Retention Data Set (RDS) to tape files as they are created in realtime. This feature is activated by adding a TMSRDS DD statement to the TMSINIT procedure that points to your installation's RDS. When TMSINIT finds the TMSRDS DD defined, it opens and reads the RDS, tabling all expiration rules in a memory resident table in ECSA (Extended Common Storage Area.) As each tape file being created goes through data set CLOSE processing, CA 1 accesses the memory resident RDS table to perform a lookup on any expiration rules matching the data set name being created. When the most specific match is made, the volume or DSNB (if a secondary file is being created) record is updated with the expiration date.

Note: With the exception of SELECT=ALL processing, Realtime Expiration uses the same matching logic as the TMSEXPDT utility. Since SELECT=ALL requires that the TMC be processed for all data sets that match the updated rule, this function may only be performed using TMSEXPDT.

When Realtime Expiration is activated on all systems in a shared TMC environment, the batch TMSEXPDT utility no longer needs to be run daily. However, TMSEXPDT continues to be supported for those users not implementing Realtime Expiration and to allow users to re-apply retention rules for tape files previously created (SELECT=ALL processing).

In multiple system or Parallel Sysplex environments, attention and care should be taken to keep the rules synchronized on all systems sharing the TMC. After changing the rules, the in-memory rules can be refreshed by simply running TMSINIT with the TMSRDS DD statement defined to point to the updated RDS. This should be done on all systems sharing the TMC to ensure that the same set of rules are applied, regardless of which system the tape file is created on.

Installations with very large Retention Data Sets should evaluate the performance of this facility prior to implementing the feature in a production environment. While the rules are accessed directly in memory, very large RDS tables may take longer to process, resulting in delays in CLOSE processing.

The Realtime Expiration feature can be deactivated by removing the TMSRDS DD statement and running TMSINIT. No system option is required to activate or deactivate this feature, however, the Retention Override parameter must be turned on to allow Realtime Expiration to override expiration dates set through JCL, as it is required for processing TMSEXPDT.