Virtual Tape Library

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A Virtual Tape Library (VTL) is a data storage virtualization technology used typically for archival storage purposes. A VTL presents a storage component (usually hard disk storage) as tapes available for use with tape drive and media changer emulations.

Virtualizing the storage as tape hardware allows integration of VTLs with existing archiving policies and backup software while taking advantage of the benefits of storage virtualization. The benefits of tape virtualization include storage consolidation and faster data restore processes.

Most current VTL solutions use ATA or SATA disk arrays as the primary storage component due to their relatively low cost. The use of array enclosures increases the scalability of the solution by allowing the addition of more disk drives and enclosures to increase the storage capacity.

By backing up data to disks instead of tapes, VTL often increases performance of both backup and recovery operations. In some cases, the data stored on the VTL's disk array is exported to other media, such as tapes, for disaster recovery purposes.

Historically, tape drives and libraries mostly featured SCSI Parallel Interface and Fibre Channel external interfaces. Likewise, VTL solutions generally support popular SCSI transport protocols such as SPI, Fibre Channel, and iSCSI.