Multipath architecture

The multipath architecture feature of the tape library allows Open Systems applications to share the robotics of the library.

The tape library features storage area network (SAN) ready multipath architecture. This architecture allows homogeneous or heterogeneous Open Systems applications to share the library's robotics without middleware or a dedicated server (host) acting as a library manager. The SAN-ready multipath architecture makes sharing possible by partitioning the library's storage slots and tape drives into logical libraries. Servers can then run separate applications for each logical library. This partitioning capability extends the potential centralization of storage that the SAN enables. Partitioning also provides investment protection if your application does not support the mixing of drive generations and media in the same logical library.

The multipath architecture of the tape library is designed to provide the capability to share the library robotics. The sharing is accomplished first by partitioning the library into as many as 128 logical libraries (up to the number of drives installed). Then, each logical library is assigned its own separate and distinct drives, storage slots, and control paths. Input/output (I/O) slots are shared on a first-come-first-serve basis. This type of partitioning is designed to allow heterogeneous applications to share the library robotics independent of each other. Cartridges under library control are not shared between logical libraries, nor are they allowed to be moved between logical libraries. An example of heterogeneous sharing is a Microsoft Windows application that is using the drive and storage slots of one logical library, while a UNIX application uses the drive and slots of another logical library. Logical libraries can also be used for separating LTO 5 tape drives and cartridges from later LTO or 3592 tape drives and cartridges, for applications that do not support mixing the drives in the same logical library.

Whether partitioned or not, the tape library is certified for SAN solutions (such as LAN-free backup).

The multipath architecture allows for more than one control path to be configured for any one logical library. A control path is a logical path into the library through which a server sends standard SCSI Medium Changer commands to control the logical library. Multiple control paths reduce the possibility of a failure in one control path to cause the entire library to become unavailable. Use of the control path failover feature further reduces that possibility.