IBM Magstar 3494 manual High Availability Model HA1, Database Information Available to a Host

Database

The library manager creates and maintains a database that contains the con®guration of the library, the physical location information for all the elements of the library serviced by the cartridge accessor, the inventory of the physical cartridge volumes and logical volumes managed by a VTS, and information about their use and current status, and the status of each 3490E/3590 device and virtual device. As operations progress through the library, the database is dynamically updated on the disk drive to re¯ect the current status of the library.

High Availability (Model HA1)

If the high availability model is installed, a second library manager is provided in the right-hand service bay. Each library manager contains two hard (disk) drives, a primary and secondary disk. Under normal operation, one library manager is the active library manager and the other library manager is the standby library manager. The active library manager, on its primary disk, creates and maintains the database, which is dynamically updated to re¯ect the current status of each library. The standby library primary disk contains a back-up of the database, which is also dynamically updated to re¯ect the current status of the library.

If the active library manager fails, the standby library manager automatically becomes the active library manager and takes control of operations. A new backup database is then created on the active library manager's secondary disk drive. The new active library manager runs in degraded mode until the failing library manager is repaired. This allows continued operation of the 3494.

Database Information Available to a Host

The library manager maintains information in its database that may be requested through a host. The form of the particular host request is dependent on the host environment. The following information is available through the host:

Category inventory data

Records for 100 volumes in the library for the category speci®ed, starting after the sequence number speci®ed by the request. If fewer than 100 volumes are in the category, all of the remaining records are returned. Each record contains the current status and media-type for a volume in the inventory.

Device data

Information about any particular device within the library. This information includes the device states, volser, and category of the mounted cartridge.

Expanded volume data

More detailed information about the current status and media-type for a speci®c volume than the volume data information request. It does not provide physical location information for the volume.

Inventory volume count

The number of volumes in the library for either the entire inventory or a speci®ed category.

Inventory data

Records for 100 volumes in the library, starting after the volume speci®ed by the request. If fewer than 100 volumes remain in the library, all of the

28Magstar 3494 Tape Library Operator Guide