ACSLS, SCSI, VTL, and 349x tape-library sharing

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When IBM Storage Protect servers share an ACSLS, SCSI tape, virtual tape library (VTL), or 349x tape library device, one server, the library manager owns, and controls the device.

The library manager operations include checking volumes into and out of the library, labeling volumes, mounting and dismounting volumes, auditing volumes, and tracking an inventory of library contents. The storage agents, along with other IBM Storage Protect servers that share this library are library clients. As a library client, the storage agent stores data and requests drives, tapes, and volumes.

When the IBM Storage Protect server is also the library manager for the devices where data is stored by the storage agent, the storage agent communicates requests to this IBM Storage Protect server. When the IBM Storage Protect server is another library client, the storage agent communicates requests for itself or the metadata server directly to the library manager.

The library manager server can support library clients that are at the same or earlier version as the library manager. Library clients at a higher version than the library manager are not supported. When you use a shared ACSLS library, the library manager must be a IBM Storage Protect server on a AIX, HP-UX, Linux, Solaris, or Windows operating system.

Note: If you define a library manager server that is shared with the IBM Storage Protect server, the SANDISCOVERY option must be set to ON. By default, this option is set to OFF.

A library client requests shared library resources, such as drives or media, from the library manager, but uses the resources independently. The library manager coordinates the access to these resources. Data moves over the SAN between the storage device and either the library manager or the library client. Either the library manager or any library client can manage the LAN-free movement of client data when the client system includes a storage agent.

In this library-sharing environment, the most important relationship is the one between the server and the storage agent. The server, working with the storage agent, manages the storage hierarchy. The server could be a library client or library manager. The server is responsible for the following operations:

  • Migrations
  • Expiration of files that is based on policy information
  • Reclamation of free space on volumes and consolidation of the volumes
  • Disaster recovery

The storage agent contributes information to the storage hierarchy through various operations, but this role is independent of the library-sharing role.

The following library manager and library client configurations are represented in Figure 1:

  • A IBM Storage Protect server library manager manages data of a client, which is stored in a tape library.
  • A IBM Storage Protect server library client manages data of a client, which is stored in a tape library.
Figure 1. Library manager and client LAN-free configuration
A single client system is connected to two other client systems and to a SAN. All the client systems are connected to a LAN. A IBM Storage Protect server, acting as a library manager, is connected to the LAN and to the SAN. A IBM Storage Protect server, acting as a library client, is also connected to the LAN and to the SAN. A tape library is connected to the SAN.
Tip:
  • An environment can have a library manager without a library client.
  • In an environment where ACSLS library support is required, the library client and library manager can be on a IBM Storage Protect server on AIX, HP-UX, Linux, Solaris, or Windows.