NetApp Casts VTL Shadow

Network Appliance doesn't have data de-duplication yet for its NearStore Virtual Tape Library (VTL), but it does have a feature geared to making life easier for storage administrators. (See NetApp Integrates VTL and NetApp Readies Virtual Tape.)

NetApp and partners Symantec, BakBone, CommVault, and Syncsort today said they are working to integrate what NetApp calls its Shadow Tape function into backup applications from the partners. Specifically, Shadow Tape lets administrators retain a copy of a backup on the NearStore VTL instead of deleting it after the backup gets written to tape. The reason for doing so is because the copy can be restored quicker from disk than from tape.

Here's the problem NetApp aims to solve: Without adequate integration between a VTL and a backup application, admins looking to restore from disk must "hide" the VTL copy during backup. If they want to restore from the backup copy, the backup application looks to recover from tape. The administrator must then "unhide" the VTL copy before it can be restored.

Once the backup vendors working with NetApp build in Shadow Tape support, users will be able to set policies to automatically hide and unhide the VTL copy through the supported backup applications. Since VTL uses the same backup process and backup applications as tape backup, integration with the backup software is crucial.

"One of the top concerns of VTL users is backup application integration," says Krish Padmanabhan, NetApp's GM of its VTL unit. "They want the backup app to be smart enough to know there's a backup tape between the VTL and the physical library."While NetApp has backup software market leader Symantec on board to support Shadow Tape, today's announcement did not include the next two largest backup vendors -- EMC and IBM. Perhaps it's just coincidence, but those vendors have their own VTL products.

EMC added the equivalent of Shadow Tape between its Legato Networker backup software and Clariion Disk Library VTL in April, but that company did not improve integration with other vendors' backup apps. (See EMC Adds Low-End VTL.)

Will NetApp bend on adding EMC and IBM to its integration roster? According to NetApp, APIs will be available for all the backup vendors to write to. An EMC spokesman says the company was not aware of the program before today. IBM did not return requests for comment by press time.

The importance of integration between VTL and backup applications can be debated. Although administrators seek better integration, most VTL vendors have been concentrating on data de-duplication to make their products easier to scale and perform better. (See De-Dupers Demand Disk Mindset.)

According to market research firm TheInfoPro, integration with backup apps is one of the major problems of VTLs but not the primary one. Interviews with 155 Fortune 1000 firms in the firm's most recent survey found lack of scalability the main complaint as users find VTLs are not expandable enough to meet enterprise needs, says TIP's managing director Rob Stevenson.Poor backup application integration was the second most frequent pain point, followed by poor de-duplication. However, improved de-duplication would actually help solve the scalability problem. Data de-duplication, which compresses data, helps scalability by reducing capacity needs and allows more data to be written to the VTL.

FalconStor, whose VTL software runs on systems sold by NetApp rivals EMC, IBM, and Sun, recently added data de-duplication. (See FalconStor Plots De-Dupe Debut and FalconStor Launches SIR.) Data Domain and Dilligent Technologies also support data de-duplication in their VTLs, and Sepaton expects to have it by the end of the year.

NetApp has de-dupe on its roadmap but isn't saying when it expects to have it ready.

The timing, or lack thereof, could be a drawback. "[De-dupe is] starting to become a must-have," TIP's Stevenson says. "Lack of de-duplication is one of the reasons VTL doesn't scale. Now that FalconStor has it, it can hurt NetApp that it doesn't do data de-dupe yet."

Shadow Tape wasn't the only backup news today. Also:

Dave Raffo, News Editor, Byte and Switch