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The Tivoli Storage Manager devices and media are represented by objects that you define and that are stored in the database. The objects contain information about the devices and media. You can query, update, and delete the objects. The storage objects are:
The following sections describe these objects.
These three objects taken together represent a physical storage entity as shown in Figure 7.
Figure 7. Removable Media Devices Are Represented by a Library, Drive, and Device Class
A physical library is a collection of one or more drives that share similar media mounting requirements. That is, the drive may be mounted by an operator or by an automated mounting mechanism. A library object definition specifies the library type (for example, SCSI or 349X) and other characteristics associated with the library type (for example, the category numbers used by an IBM 3494 library for private and scratch volumes).
Each drive mechanism within a device that uses removable media is represented by a drive object. For devices with multiple drives, including automated libraries, each drive is separately defined and must be associated with a library. Drive definitions can include such information as the element address (for drives in SCSI libraries), how often the drive is cleaned (for tape drives), and whether or not the drive is online.
Each device defined to Tivoli Storage Manager is associated with one device class. That device class specifies a device type and media management information, such as recording format, estimated capacity, and labeling prefixes. Device classes for a tape or optical drives, must also specify a library.
A device type identifies a device as a member of a group of devices that share similar media characteristics. For example, the 8MM device type applies to 8mm tape drives. Device types include a variety of removable media types and also FILE and SERVER:
You can use FILE volumes as a way to use disk storage without having to define volumes. FILE volumes can also be useful when transferring data for purposes such as electronic vaulting.
Virtual volumes can be used for the following:
A storage pool is a collection of storage pool volumes that are associated with one device class and one media type. For example, a storage pool that is associated with a device class for 8mm tape volumes contains only 8mm tape volumes. You can control the characteristics of storage pools, such as whether scratch volumes are used. For details about defining storage pools, see Chapter 9, Managing Storage Pools and Volumes.
Tivoli Storage Manager supplies default disk storage pools. For more information, see Configuring Random Access Volumes on Disk Devices.
Figure 8 shows storage pool volumes grouped into a storage pool. Each storage pool represents only one type of media. For example, a storage pool for 8mm devices represents collections of only 8mm tapes.
Figure 8. Relationships of Storage Pool Volumes, Storage Pools, and Media
For DISK device classes, you must define volumes. For other device classes, such as tape and FILE, you can allow the server to dynamically acquire scratch volumes and define those volumes as needed. For details, see Preparing Volumes for Random Access Storage Pools and Preparing Volumes for Sequential Access Storage Pools.
One or more device classes are associated with one library, which can contain multiple drives. When you define a storage pool, you associate the pool with a device class. Volumes are associated with pools. Figure 9 shows these relationships.
Figure 9. Relationships between Storage and Device Objects
For more information about the storage pool and volume objects, see Chapter 9, Managing Storage Pools and Volumes.
Data movers are devices that accept requests to transfer data from applications such as Tivoli Storage Manager. Data movers transfer data:
You must define a data mover if you will be using network-attached storage. Among other characteristics, you must specify the data format that will be used and the data mover address.
For more information about the data mover object, see Defining Data Movers and Managing Data Movers.
Paths allow access to drives and libraries and drives. A path definition specifies a source and a destination. The source accesses the destination, but data can flow in either direction between the source and destination. Here are a few examples of paths:
For more information about the path object, see Defining Paths and Managing Paths.
You need to define a server object, for the following purposes:
Among other characteristics, you must specify the server TCP/IP address.
When data is to be stored in or retrieved from a storage pool, the server does the following:
If no defined volumes in the storage pool can be used, and if the storage pool allows it, the server selects a scratch volume.
If a scratch mount is requested, the server checks the library's volume inventory for a scratch volume. If one is found, its status is changed to private, it is mounted in the drive, and it is automatically defined as part of the original storage pool. However, if the library's volume inventory does not contain any scratch volumes, the mount request fails.