Volume management by the book: the NAStore Volume Manager

The NAStore Volume Manager provides controlled access to removable media under UNIX. It is compatible with the latest informal consensus of the IEEE Storage System Standards Working Group. The modular design allows it to manage robotic and manual drives of various types in many locations: a UNIX daemon fields requests and passes them to the appropriate ´Repository Controller´ based on the medium and location of the volume. At NAS the repositories are a vault and a farm of StorageTek ACS robots. Access permissions are handled analogously to the UNIX file system, with noaccess-read-readwrite separately assignable for owner, group, and world. A suite of user utilities allows volume allocation, mounting, moving, listing, access modification, and deallocation to be performed on the UNIX command line; a programmatic interface allows programs (such as a file migration manager) to accomplish the same functions. Initial testing, operational experience, and possible improvements are discussed.<>