Batch scheme for magnetic-tape operation

A tape library system for controlling an operation of a tape library system comprising at least one magnetic-tape drive unit, at least one accessor, and a plurality of tape cartridges, wherein the operation of the tape library system comprises a usage optimization of available resources of the tape library system, the tape library system comprising:

• one or more processors and a memory operatively coupled to the one or more processors, wherein the memory stores program code portions which, when executed by the one or more processors, enable the one or more processors to;
• determine a load value of the resources of the tape library system;
• accumulate requests to a tape cartridge in a batch before using the tape library system to physically access the tape cartridge;
• dynamically adjust a number of requests in the batch before physically accessing the tape library system depending on the load value such that a response time of the tape library system is optimized;
• and
• detect that the at least one accessor has become a bottleneck upon a determination that an expression is true, wherein the expression comprises:
• a
• <
• (
• 2
• *
• R
• *
• d
• )
• /
• (
• BI
• +
• U
• +
• M
• )
• ,
• wherein
• a=a number of accessors in the tape library system;
• d=a number of magnetic-tape drive units in the tape library system;
• R=a robot transfer time;
• BI=an average service time of an initial request;
• U=an average unmount time of a tape cartridge;
• and
• M=an average mount time for a tape cartridge.

A computer program product for controlling an operation of a tape library system comprising at least one magnetic-tape drive unit, at least one accessor, and a plurality of tape cartridges, wherein the operation of the tape library system comprises a usage optimization of available resources of the tape library system, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions being executable by one or more computing systems or controllers to cause the one or more computing systems to:

• determine a load value of the resources of the tape library system;
• accumulate requests to a tape cartridge in a batch before using the tape library system to physically access the tape cartridge;
• dynamically adjust a number of requests in the batch before physically accessing the tape cartridge dependent on the load value such that a response time of the tape library system is optimized;
• and
• detect that the at least one accessor has become a bottleneck upon a determination that an expression is true, wherein the expression comprises:
• a
• <
• (
• 2
• *
• R
• *
• d
• )
• /
• (
• BI
• +
• U
• +
• M
• )
• ,
• wherein
• a=a number of accessors in the tape library system;
• d=a number of magnetic-tape drive units in the tape library system;
• R=a robot transfer time;
• BI=an average service time of an initial request;
• U=an average unmount time of a tape cartridge;
• and
• M=an average mount time for a tape cartridge.