Hierarchical Storage Management (HSM)

Hierarchical storage management (HSM) provides an automatic way of managing and distributing data between the different storage layers in order to meet the users' needs for accessing data while minimizing the overall cost.

The concept of HSM involves the placement of data items in such a way as to minimize its accessibility. BRMS provides an interface to utilize this feature.
Note: The following are brief descriptions of the HSM features. To find out more information about how to setup BRMS for HSM, refer to Hierarchical Storage Management.


Through the use of BRMS migration control groups, you can select which data to move from faster, relatively expensive DASD to slower but less costly DASD. You might also set these control groups up to move the data in the opposite direction if it become more frequently accessed.


Through the use of BRMS archive control groups, you can define criteria to archive less frequently used data from disk to less expensive media (tape or optical). The criteria can be based on inactivity limit, size, or even days used per month. Once the data meets the criteria, it is then saved to tape and deleted from the system, no longer taking up that much-needed space.
Note: The archive feature supports independent ASPs and encryption. Archive control groups have restrictions and setup for these capabilities that are similar to the restrictions and setup for backup control groups. For more information about independent ASPs, refer to Backup and recovery of auxiliary storage pool devices. For more information about encryption, refer to Software encryption using BRMS. Independent ASPs and encryption are not documented in Hierarchical Storage Management.

Dynamic Retrieval

Besides having the ability to archive the data off to removable media, it is just as important to recover the data. A user can easily recover the data using the normal BRMS recovery process; however, BRMS also provides Dynamic Retrieval of the data. This allows the recovery action to be prompted by a simple access of the data. For example, if a database file has been archived, but an application actually tries to access this file, BRMS will then be asked to restore the file. After the file is restored, the application continues on. There is no major disruption in the application other than a delay for the restore of the file.