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Administrator's Guide


Configuring Libraries Controlled by Media Manager Programs

You can use an external media manager program with Tivoli Storage Manager to manage your removable media. While the server tracks and manages client data, the media manager, operating entirely outside of the I/O data stream, labels, catalogs, and tracks physical volumes. The media manager also controls library drives, slots, and doors.

A programming interface is provided that lets you use a variety of media managers. See Appendix A, External Media Management Interface Description for a complete description of this interface. See Setting up Tivoli Storage Manager to Work with an External Media Manager for setup procedures.

To use a media manager with Tivoli Storage Manager, define a library that has a library type of EXTERNAL. The library definition will point to the media manager rather than a physical device.

Setting up Tivoli Storage Manager to Work with an External Media Manager

To use the External Media Management Interface with a media manager, do the following procedure. This example is for an 8mm medium-changer device containing two drives.

  1. Set up the media manager to interface with Tivoli Storage Manager. For more information, see Appendix A, External Media Management Interface Description.
  2. Define an external library named MEDIAMGR:
    define library mediamgr libtype=external
    
    Note:
    You do not define the drives to the server in an externally managed library.
  3. Define a path from the server to the library:
    define path server1 mediamgr srctype=server desttype=library 
    externalmanager=/u/server/mediamanager
    

    In the EXTERNALMANAGER parameter, specify the media manager's installed path. For more information about paths, see Defining Paths.

  4. Define device class, EXTCLASS, for the library with a device type of 8mm:
    define devclass extclass library=mediamgr mountretention=5 mountlimit=2
    

    The MOUNTLIMIT parameter specifies the number of drives in the library device.

    Notes:

    1. For environments in which devices are shared across storage applications, the MOUNTRETENTION setting should be carefully considered. This parameter determines how long an idle volume remains in a drive. Because some media managers will not dismount an allocated drive to satisfy pending requests, you might need to tune this parameter to satisfy competing mount requests while maintaining optimal system performance.

    2. It is recommended that you explicitly specify the mount limit instead of using MOUNTLIMIT=DRIVES.
  5. Define a storage pool, EXTPOOL, for the device class. For example:
    define stgpool extpool extclass maxscratch=500
    

    Key choices:

    1. Scratch volumes are labeled, empty volumes that are available for use. If you allow scratch volumes for the storage pool by specifying a value for the maximum number of scratch volumes, the server can choose from the scratch volumes available in the library, without further action on your part. If you do not allow scratch volumes, you must perform the extra step of explicitly defining each volume to be used in the storage pool.

    2. Collocation is turned off by default. Collocation is a process by which the server attempts to keep all files belonging to a client node or client file space on a minimal number of volumes. Once clients begin storing data in a storage pool with collocation off, you cannot easily change the data in the storage pool so that it is collocated. To understand the advantages and disadvantages of collocation, see Keeping a Client's Files Together: Collocation and How Collocation Affects Reclamation.

Managing Externally Controlled Tivoli Storage Manager Media

Refer to the documentation for the media manager for detailed setup and management information. The following are some Tivoli Storage Manager-specific issues that you should consider:

Labeling Media
The media manager handles the labeling of media. However, you must ensure that an adequate supply of blank media is available.

Checking Media into the Library
Externally managed media is not tracked in the Tivoli Storage Manager volume inventory. Therefore, you will not perform library check-in procedures.

Using Tivoli Disaster Recovery Manager
If you are using DRM, you can use the MOVE DRMEDIA command to request the removal of media from the library. For more information, see Chapter 23, Using Tivoli Disaster Recovery Manager.

Migrating Media to External Media Manager Control
We strongly recommend that you not migrate media from Tivoli Storage Manager control to control by an external media manager. Instead, use external media management on a new Tivoli Storage Manager configuration or when defining externally managed devices to the server.

Deleting Tivoli Storage Manager Storage Pools from Externally Managed Libraries
Before deleting externally managed storage pools, first delete any volumes associated with the Tivoli Storage Manager library. For more information, see Deleting a Storage Pool Volume with Data.

Troubleshooting Database Errors

Error conditions can cause the Tivoli Storage Manager volume database and the media manager's volume database to become unsynchronized. The most likely symptom of this problem is that the volumes in the media manager's database are not known to the server, and thus not available for use. Verify the Tivoli Storage Manager volume list and any disaster recovery media. If volumes not identified to the server are found, use the media manager interface to deallocate and delete the volumes.

Using the Devices to Store Client Data

After you have attached and defined your devices, you can store client data in two ways:


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