Using the Basic Components › Externalization Groups and Subgroups

Externalization Groups and Subgroups

The Externalization Groups, assigned by the mount interception filters, are a way to associate data with similar storage management objectives. Test, production, and system data can be assigned to different groups, like they are assigned to different storage groups or pools on DASD.

The different groups can be customized to meet the storage management requirements of the data. Test may not be encrypted and may have only a single copy created when Externalized. Production may be encrypted and have two copies created when Externalized.

Each group is automatically broken down into three subgroups: Short, Medium, and Long. The expiration date of the data written to the Virtual Volume determines which subgroup is assigned. The expiration dates and retention periods used for the breakdown can be customized in the Group Definitions.

The group definitions also contain prioritization and cache residence attributes which allow you to influence which group is Externalized first and how long to keep one group’s Externalized Virtual Volumes in cache versus another. This allows you to fine tune the Externalization process and which Virtual Volumes remain available in cache for immediate reuse.

Note: For a complete description of the Group Definitions, see the chapter “The Parameter Library (PARMLIB)” in the Configuration Guide.