Administrator's Guide


How Tivoli Storage Manager Uses Sequential Access Devices

Each TSM library is a collection of drives. A device class, which governs how data is stored, is associated with one library. When you define a storage pool, you associate the pool with a device class. Volumes are associated with pools. Figure 12 shows these relationships.

Figure 12. Relationships between Storage and Device Objects

Relationships between Storage and Device Objects


When the TSM server determines that data is to be stored into or retrieved from a storage pool, it performs the following procedure:

  1. Selects a volume from the given storage pool. The selection is based on the type of operation:

    Retrieval
    The name of the volume is stored in the server database.

    Store
    If a defined volume in the storage pool can be used for the data being stored, the server chooses this volume name.

    If no defined volumes in the storage pool can be used for the data, and if the MAXSCRATCH parameter of the storage pool permits it, the server may try a scratch mount.

  2. Determines the name of the library containing the drives that can be used for the operation by checking the device class associated with the storage pool.

  3. Performs the volume mount operation:

  4. Dismounts the volume from the drive when it has finished accessing the volume and the mount retention period has elapsed.


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