VTLs: Going beyond data de-dupe


Virtual tape libraries (VTLs) have come of age, solidifying their position as a preferred technology for tackling backup windows and data growth.

A recent survey of 114 North American IT professionals conducted on behalf of InfoStor by the TechValidate research firm indicates that most users place VTLs on a pedestal when compared to tape libraries. Managing VTLs is considered a simpler task than managing tape by 66% of those polled, while 77% say VTLs are easier to scale.

A key part of the VTL maturation process has been the evolution of data de-duplication from a VTL feature to a VTL staple. For example, 68% of the TechValidate survey respondents—all of whom work in medium or large enterprise organizations and have data protection experience—say de-duplication is a “must-have” feature for any VTL they may consider purchasing.



Additionally, 84% of those surveyed say vendor claims about de-duplication ratios and performance influence VTL buying decisions.

Now that de-duplication and VTLs have become synonymous, the conversation is quickly turning from data reduction to higher-level issues, with vendors focusing on scalability, centralized management, replication and energy efficiency.

At first blush, the VTL market may seem crowded; however, look a bit deeper and today’s VTL systems have a lot more in common than speeds, feeds and storage optimization features.


According to Enterprise Strategy Group analyst Lauren Whitehouse, FalconStor Software’s VTL platform still serves as the foundation for close to half of the products in the space. For example, Copan Systems’ Revolution 300T/TX VTL, EMC’s DL4000 Disk Library, IBM’s TS7520 Virtualization Engine, Pillar Data Systems’ Axiom Application-Aware Storage for VTL, Spectra Logic’s RXT as VTL product, Sun Microsystems’ StorageTek VTL and, of course, FalconStor’s own VTL product are all based on FalconStor technology.

Quantum and Sepaton also supply VTL technology to other vendors. Quantum offers its own DXi series of VTL appliances, as well as supplying EMC with the technology used in the EMC Disk Library 3D. Sepaton, which offers the S2100 line of enterprise and departmental VTLs, also provides its DeltaStor de-duplication technology to Hewlett-Packard for the HP Virtual Library System (VLS).

The rest of the market is comprised of systems from a handful of additional vendors. Data Domain offers a VTL option for its disk-based backup appliances, Fujitsu-Siemens sells a VTL called CentricStor, Gresham Enterprise Storage has the Clareti VTL, IBM features the TS7650G ProtecTIER Gateway product based on its acquisition of Diligent Technologies, NetApp’s VTL is NearStore, and Overland Storage offers the REO VTL.

Recent VTL enhancements

The latest VTL news from FalconStor centers on CIFS and NFS connectivity and support for the Symantec OpenStorage (OST) API. The company has extended the de-duplication capabilities of its VTL to NAS-based disk-to-disk (D2D) backups via the file-interface de-dupe system (FIDS). The FIDS provides CIFS and NFS connectivity for block-level de-duplication and immediate file-level access to the de-duplication repository. The FIDS software presents a network share interface as a backup repository, offering users a space-saving option for writing data efficiently to disk.

FalconStor also improved support for high-performance network connectivity. The company’s VTL 5.1 software now supports 10Gbps iSCSI and 8Gbps Fibre Channel for faster backups. VTL 5.1 systems can now scale in performance up to 1.5GBps per node with up to eight nodes per logical deployment of a VTL. This extends the VTL’s backup capability up to 43TB per hour for each VTL deployment.

Also new is the availability of the OST Option, which turns FalconStor’s VTL into a native storage target for Symantec’s Veritas NetBackup 6.5. The Symantec OST API provides a common interface to third-party disk targets, allowing NetBackup software to treat any NAS or VTL target as disk, eliminating the need for a VTL interface in NetBackup environments.

The native connectivity lets NetBackup handle disk-to-disk transactions, enabling features such as high-speed backup and recovery to intelligent disk devices over IP or Fibre Channel.

Quantum recently refreshed the capacity and replication features for its DXi7500 disk-based backup system, the first significant round of upgrades for the de-duplicating storage platform since its launch.

Quantum increased the usable disk capacity of the DXi7500 by more than 20% through support for 1TB SATA drives. The addition of 1TB drives is accompanied by an upgrade to double-parity RAID-6 technology (from RAID 5) to increase overall data protection. The largest model now offers a maximum usable capacity of 220TB.

On the software front, Quantum expanded its replication options for multi-site environments and tightened its ties with backup and replication software from EMC, Oracle, and Symantec.

The new software release includes enhancements for more granular replication and synchronization of data, providing replication at the cartridge or file/directory level, and automatically making data available immediately at the target for restores.

Quantum has also integrated the DXi7500 with Symantec’s OST API, and added support for application-aware tape creation support through EMC NetWorker 7.5, facilitating the direct transfer of data from the DXi7500 to tape while under the application’s control.

Quantum also entered into a partnership with Dell and EMC (see sidebar, above).

Hewlett-Packard is now shipping its line of StorageWorks Virtual Library System (VLS) VTLs equipped with de-duplication software OEM’d from Sepaton, as well as a homegrown de-duplication feature for its family of disk-based backup systems for SMBs.

HP provides two distinct methods of data de-duplication. For enterprise customers, the company offers de-dupe as an option for its VLS platforms based on Sepaton’s DeltaStor technology. For SMBs, HP has integrated its own de-duplication functionality into the StorageWorks D2D Backup Systems.

The VLS provides virtual tape for HP’s Enterprise Virtual Array (EVA) environments by integrating into existing data-protection processes. The VLS systems range in capacity from 105.6TB (VLS6000) to 1,080TB (VLS12000), with 4Gbps Fibre Channel connectivity, maximum performance of up to 4,800MBps, and the ability to emulate up to 128 virtual libraries and 1,024 virtual drives.

Looking ahead

VTL vendors are typically reluctant to disclose what types of upgrades or enhancements we might see in 2009 beyond the standard capacity and processor refreshes, but combining de-duplication and replication to reduce capacity requirements at remote sites is a no-brainer.

Jay Livens, director of marketing for Sepaton, says 2009 is all about return on investment (ROI) for end users. “One of the things our customers are looking for is a de-duplication-enabled replication solution,” he says.

Livens would not specify, but a likely conclusion would be a product upgrade that combines Sepaton’s existing Site2 replication technology with DeltaStor de-duplication to extend de-dupe to remote/branch offices.

“Companies are taking a hard look at the projects they fund, and they’re more likely to move ahead with something like de-duplication-enabled replication rather than a hardware refresh,” says Livens. “It’s about what they can do to store more data in less space.”

Kevin Wise, a senior product manager at Overland Storage, says the disk-based backup market as a whole is moving toward broadening the application of de-duplication. “We see de-duplication stretching into nearline and online storage. It is becoming a must-have not just for VTLs, but in the backup-to-disk market in general.”

Wise adds that energy-efficient technologies will soon find their way into VTLs. “Drive spin-down capabilities are also a must-have,” he says.

Though some VTL vendors, such as Copan, already provide massive array of idle disks (MAID) technology, look for Overland and other vendors to begin adding MAID and other power-saving features and drives to their systems later this year.

This article was originally published on March 01, 2009