ADSM supports many devices for storing data. Devices known to ADSM may be devices that exist as real physical devices, such as a disk drive or a tape drive. Devices may also be logical devices, such as files on a disk (FILE device type) or storage on another server (SERVER device type).
ADSM represents both physical and logical devices with administrator-defined ADSM storage objects: the device class, the library, and the drive. The storage objects, which you define when you configure devices for ADSM, contain information for the management of devices and media.
At a minimum, each type of device requires a device class. The device class contains information for the management of devices and media that are of a specific device type. The device type determines whether ADSM also requires a library and drive definition. For example, a manually mounted tape device requires a device class, a library, and a drive definition. See the following sections for details:
For a summary, see Table 3.
For details about devices that are supported, visit the ADSM web site at this address:
Magnetic disk devices are the only devices in the random access category so they all share the same ADSM device type and device class: DISK. ADSM predefines the DISK device class.
Figure 3. Magnetic Disk Devices Are Represented by Only a Device Class
A tape or optical device is represented by a library and a drive in addition to a device class.
Sequential devices for which an operator must perform volume mounts require a different ADSM library than devices that are associated with an automated library with robotics. ADSM provides a manual library type for stand-alone devices that are loaded by an operator and automated library types for devices loaded by a robot.
Figure 4. Removable Media Devices Are Represented by a Library, Drive, and Device Class
Sequential devices that are managed by an external media management system require a library definition, but not a drive definition.
ADSM allows administrators to create volumes on server disk space that have the characteristics of sequential access volumes such as tape. ADSM supports these sequential volumes through the FILE device type. FILE is a sequential device type that, because it is on disk, does not require the administrator to define a library or drive object; only a device class is required.
FILE volumes are often useful when transferring data for purposes such as electronic vaulting.
ADSM allows administrators to create volumes that exist as archived files in the server storage of another ADSM server. These virtual volumes have the characteristics of sequential access volumes such as tape. ADSM supports virtual volumes through the SERVER device type. The SERVER device type does not require the administrator to define a library or drive object. The administrator must define a device class and a server that will store the data.
Virtual volumes are useful for purposes such as the following: