Logical libraries

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A logical library is a set of tape drives and tape cartridges that are defined as a virtualized library by a user. The ability to partition logical libraries makes it possible for similar and dissimilar hosts (servers) to share a single physical library. As a result, hosts can simultaneously run separate software applications in separate logical libraries.

The following are two reason that a logical library is created:
  • Share the library for multiple applications: You can partition your library so that it processes commands from Application 1 (about Department A) in Logical Library 1, commands from Application 2 (about Department B) in Logical Library 2, and commands from Application 3 (about Department C) in Logical Library 3. In this configuration, the tape drives and tape cartridges in each logical library are dedicated to that library and are not shared among other libraries. Commands that are issued by the applications travel to the library through three unique control paths. Thus, the data processing for Department A is confined to the tape drives and tape cartridges in Logical Library 1, processing for Department B is confined to the tape drives and tape cartridges in Logical Library 2, and so forth.
  • Share the library to support mixed drive types for any application: For TS4500, you can use multiple logical libraries for applications that do not support mixed drive types and media in the same logical library by partitioning the physical tape library to keep them separate. For example, you can partition LTO 6 and LTO 5 tape drives and their media into two separate logical libraries. Diamondback does not support mixed media within one library.

For TS4500, the first logical library can be configured with the Library Setup wizard that allows you to define your library name, date and time, and the initial logical library. You can choose the library name and the type of encryption mode to use as part of this setup. Otherwise, all drives in the library and the cartridge range 000000-ZZZZZZ are assigned.

For Diamondback, an initial logical library is automatically configured for you when the library is delivered. This default logical library has the name Default with all drives in the library assigned, the cartridge range 000000-ZZZZZZ assigned, and encryption disabled. This may be modified after installation or new logical libraries partitioned to subdivide the drives and cartridges further.