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Administrator's Guide
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.
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.
- Set up the media manager to interface with Tivoli Storage Manager.
For more information, see Appendix A, External Media Management Interface Description.
- 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.
- 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.
- 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:
- 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.
- It is recommended that you explicitly specify the mount limit instead of
using MOUNTLIMIT=DRIVES.
- Define a storage pool, EXTPOOL, for the device class. For
example:
define stgpool extpool extclass maxscratch=500
Key choices:
- 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.
- 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.
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.
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.
After you have attached and defined your devices, you can store client data
in two ways:
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