Support for WORM Cartridges Realized by Linear Tape File System (LTFS)

摘要

When a WORM cartridge is formatted for Tape File System (LTFS) in advance, such as prior to shipment, Linear Tape File System Library Edition (LTFS LE) is expanded by software to reduce consumption of the index partition and to support elimination of the appending of unnecessary data. More specifically, instead of recording metadata in the index partition during normal unmounting, the metadata is recorded in separate local storage such as on hard disk drive (HDD), and the index partition is updated only when the cartridge is ejected from the library. In this way, the present invention is able to significantly reduce the frequency of index partition updates. Because an update occurs only when the user intentionally ejects a cartridge, overflow of the index partition before overflow of the data partition can be prevented.

主权项

1. A method for eliminating the appending of unnecessary data created when a tape cartridge mounted in a tape drive used in a file system is accessed (to reduce consumption of capacity in a WORM index partition), the method comprising the steps of:
(a) preparing a tape cartridge by dividing the built-in tape into two WORM partitions, recording the history of a plurality of files and metadata (including the allocation of one or more recorded files) in the one WORM data partition, and metadata in the other WORM index partition; (b) reading metadata recorded in a WORM index partition in response to an access request for a file in a tape cartridge mounted in a tape drive; (c) writing the read metadata to an index area in local storage; (d) using the metadata written to the index area to respond to the access request for the file (without using the metadata recorded in the WORM index partition); (e) determining whether or not an access request to metadata written to the index area is accompanied by an update of the metadata; and (f) writing metadata written to the index area to the WORM index partition when it has been determined that the access request is accompanied by an update of the metadata.