Transparent drive-to-drive copying

A data storage library, comprising:

• a library controller;
• a first data storage drive under direct control of the library controller;
• and
• a second data storage drive under direct control of the library controller,
• the library controller being configured to:
• initiate a copy request for a data storage cartridge located in a storage slot, wherein the data storage cartridge comprises data storage media having host data thereon;
• transparently load the data storage cartridge into the first data storage drive, wherein transparently loading the data storage cartridge into the first data storage drive comprises presenting the data storage cartridge as being located in the storage slot while the data storage cartridge is loaded in the first data storage drive;
• establish drive-to-drive communication within the data storage library for copying data from the data storage media in the first data storage drive to data storage media in a second data storage drive that is also in the data storage library;
• copy data from the data storage media in the first data storage drive to the data storage media in the second data storage drive;
• and
• in response to receiving a host request for the data storage cartridge in the first data storage drive and/or the second data storage drive, performing a sub-method comprising:
• interrupting the drive-to-drive communication,
• moving the data storage cartridge from the first data storage drive,
• continuing to report the data storage cartridge as being in the storage slot, and
• resuming the copying using a different storage drive which is not in conflict with the host request.

A computer program product, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a library controller to cause the library controller to:

• initiate, by the library controller, a copy request for a data storage cartridge located in a storage slot, wherein the data storage cartridge comprises data storage media having host data;
• transparently load, by the library controller, the data storage cartridge into a first data storage drive of a data storage library,
• the first data storage drive being under direct control of the library controller;
• establish, by the library controller, drive-to-drive communication for copying data from the data storage media at the first data storage drive to data storage media in a second data storage drive of the same data storage library,
• the second data storage drive being under direct control of the library controller,
• wherein one of the data storage drives is a utility drive which is not accessible by a host application that accesses the other of the data storage drives;
• and
• copy, by the computer, data from the data storage media in the first data storage drive to the data storage media in the second data storage drive,
• wherein transparently loading the data storage cartridge into the first data storage drive of the data storage library includes:
• presenting the data storage cartridge as being located in the storage slot while the data storage cartridge is loaded in the first data storage library.