What is a Virtual Tape Library ? QUADStor VTL Introduction

Tape technology remains the most cost effective backup solution till date. With current tape technology, tape media have a lifetime of 30 years or more and therefore are the number one choice for data archival. In recent years disk based backup gained popularity due to a drop in disk prices and due to lesser manual intervention. The performance of disk based backup is generally consider faster and individual file restores from disk are significantly faster due to faster seek times.

A VIRTUAL TAPE LIBRARY (VTL) is a disk based backup system which appears to the backup host as a real tape library system. Backup streams sent to the virtual tape drives are however written to and restored from disk. The biggest advantage of a VTL over other disk based backup solutions is its seamless integration into an existing tape backup infrastructure. Backup applications, policies, licenses etc need not change due to a VTL emulating an existing tape library system.

Benefits of a Virtual Tape Library (VTL) system

Improved backup and restore times

Disk based backup offers faster backup and restore times. Sequential access of data is still maintained by VTL system by writing the backup data to disk in a sequential manner. When compared to other disk-to-disk backup (D2D) solutions, virtual tape libraries are high performance solutions with access to the virtual devices over the storage area network (SAN) while a D2D system utilizes a NAS network. QUADStor VTL devices can be accessed over iSCSI, Fiber Channel (FC) and an InfiniBand network.

Reduced tape media handling

Handling of tape media is greatly reduced, hence lesser manual intervention is required. Only data needed for archival purposes would have to be transferred to a physical tape, reducing the amount of tape media that is eventually needed.

Easy integration and Interoperability

Tape libraries and drives from leading manufacturers are emulated. From a backup application’s point of view nothing needs to change, and to it there isn’t a difference between a virtual tape and a physical tape library. The integration of the VTL solution into the backup environment is seamless and non‐disruptive.

Multiple VTL instances

Multiple VTL instances can be created and one or more VTL instances can be dedicated to a host. Each backup server would direct its backups to its own VTL instance, removing the need for tape library sharing and backup stream multiplexing. Also multiple simultaneous backup streams improve overall backup throughput.

Dynamic disk allocation

Storage is allocated to a virtual cartridges on demand removing the need for pre allocation of disk space. Additional disk storage can be configured at a later point of time to increase the available storage capacity. Additionally disk storage can be categorized into storage pools and virtual cartridges can be associated with a storage pool. For example a WORM pool can be created for virtual cartridges with WORM property enabled.

Data deduplication

The VTL extended edition supports inline data deduplication with support for backup data streams from leading backup applications. With data deduplication, store terabytes of backup data for a fraction of the storage cost.

Data compression

Data compression decreases disk capacity requirements with translates to lesser storage costs. Data can be compressed prior to storing on disk, the compression algorithm used is fast and can achieve 2:1 compression ratios.

Disaster Recovery

With the VTL extended edition replication virtual tape data to one or more remote VTL servers for disaster recovery. Auto replication to a remote server is supported for automatic disaster recovery management

Tape Import/Export

Data from a virtual tape can be easily exported to a physical tape either manually or can be triggered by backup application. Storage pool thresholds enable retention of exported virtual tape data for certain periods of time (tape caching)

QUADStor's Virtual Tape Library

QUADStor Virtual Tape Library (VTL) software is a high performance VTL solution emulating tape libraries and drives from leading hardware vendors.


  • Windows, UNIX, Solaris Linux, IBM iSeries OS/400 and AIX connectivity
  • Fiber Channel (FC), iSCSI, InfiniBand and local SCSI access
  • Dynamic storage allocation
  • Data deduplication (Extended Edition Only)
  • VTL to VTL replication (Extended Edition Only)
  • T10 logical block protection (Extended Edition Only)
  • Physical tape import/export (Extended Edition Only)
  • Easy storage management with storage pools
  • Simple and intuitive browser based management

VTL Software

Download from https://www.quadstor.com/vtl-extended-edition-downloads.html


QUADStor VTL can be setup in a matter of few minutes.
Documentation can be accessed from https://www.quadstor.com/vtl-documentation.html

Product support

Contact vtlsupport@quadstor.com

Technical Specifications

Operating System RHEL/CentOS 7/8/9 Debian 10/11/12, SLES 15
Number of Virtual Tape Libraries Up to 128 VTLs, up to 64 drives per VTL instance
Number of Virtual Cartridges Up to 60000 virtual cartridges
Host Connectivity iSCSI, Fiber Channel (FC), and local SCSI access