The Ultra low cost StorageTek SL150 Library (1-20 drive/ 30-300 slots) now supports up to eight partitions, each with their own individual host. The library still only has one robotic arm so consolidating multiple backup services will require some consideration.
The library is a bridged device in that library commands are sent over the drive connection, so you need at least one drive per partition. You can assign more than one drive to a partition and varying amounts of slots depending on how many expansion units you have. Best of all it’s free and a breeze to configure with the remote Web GUI.
The SL150 supports all major OS’s and backup applications using LTO5HH and LTO6HH drives and its key deliverable is its ultimate flexibility and super low cost of ownership.