EMC Glossary

Virtual Tape Library (VTL)

A disk-based backup system, a virtual tape library (VTL) emulates physical tapes.

Who uses a Virtual Tape Library, and why?

Virtual tape libraries (VTLs) ingest data over a Fibre Channel interface, which enables seamless integration with many existing backup infrastructures and processes. However, most backup software supports direct backup to disk over standard file protocols such as Network File System (NFS) and Common Internet File System (CIFS), eliminating the requirement to emulate tapes.

How a Virtual Tape Library works

Traditional VTLs can only provide a front-end, fast cache to a tape library infrastructure, temporarily alleviating backup window problems. These systems can't cost-efficiently retain backup data for any length of time, and backup data is too large to be replicated or "vaulted" over a wide area network (WAN). They don't offer an evolution from tape and its associated challenges so that, ironically, tape remains the primary method of retention, recoverability, and disaster protection.

However, EMC Data Domain VTL software eliminates tape-related failures by enabling all EMC Data Domain systems to emulate multiple tape devices over a Fibre Channel interface. Data Domain VTL software emulates up to 64 virtual tape libraries with up to 540 linear tape-open (LTO)-1, LTO-2, or LTO-3 virtual tape drives. Our VTL software provides up to 64,000 virtual slots and an unlimited number of virtual tape cartridges, with the ability to dynamically change the number of virtual slots and cartridge access ports.

Benefits of a Virtual Tape Library

The ability to easily integrate with an existing Fibre Channel or tape-based infrastructure is the main benefit of a VTL. Data Domain VTL software is qualified with leading open systems and IBM enterprise backup applications, easily integrating into existing Fibre Channel storage area network (SAN) backup environments.

Data Domain systems simultaneously support data access methods through VTL over Fibre Channel, remote Network Data Management Protocol (NDMP) access over Ethernet for network-attached storage (NAS), Network File System (NFS) and Common Internet File System (CIFS) protocols over Ethernet, and EMC Data Domain Boost. This deployment flexibility along with simple administration means that users can rapidly adjust to changing enterprise requirements.