NetApps First VTL Delivers on Technologys Promise

Review: Network Appliance's VTL600 successfully merges Alacritus' VTL software with NetApp's hardware and should make NetApp a more viable player in the competitive disk-to-disk backup market.

There is an updated version of this review available. For the most recent version, click here.

Network Appliances NearStore VTL600, the first fruit of the companys acquisition of Alacritus Software, should make NetApp a more viable player in the hotly contested D2D (disk-to-disk) backup market and will be a good bet for medium- to large-size businesses.

eWEEK Labs exclusive evaluation of the VTL600 shows that the device successfully blends Alacritus VTL (virtual tape library) software with NetApps appliance hardware.

The VTL600 can create and present VTL units that existing backup software packages can easily detect and write backup jobs to. In fact, it is the seamless nature of VTL that makes the technology so compelling for IT organizations.

When backup jobs are written using VTL technology, protected data is segmented into discrete virtual tape cartridges that can be identified and retrieved by the media management software found in backup software packages.

/zimages/1/28571.gifClick here to read an interview with NetApp CEO Dan Warmenhoven about the companys new direction.

The virtual tapes and cartridges function in the same way that physical ones do, so IT staffers can continue to use the recovery tools with which they are familiar.

VTL thus provides the performance and convenience of disk-based backup without the implementation pain related to retraining personnel to use new tools.

The VTL600 also provides WAN replication capabilities, which will allow IT managers to centralize backups.

The VTL600s hardware is identical to the platform used by NetApps popular FAS 3000 midrange storage appliance and disk shelves. In its standard configuration, the VTL600 has four disk shelves and can back up data at rates close to 500MB per second.

With a minimum capacity of 4.5TB and a starting price of $114,000, the VTL600 is definitely not a solution for smaller companies on a tight budget. The VTL600 can scale up to 54TB of storage, and it can create as many as 256 virtual libraries, 1,500 virtual tape drives and 10,000 virtual cartridges.

For shops that need even more storage and performance, theres the NetApp VTL1200. That unit comes with two head units and can scale to 108TB, 512 virtual libraries and 20,000 virtual cartridges.

NetApp has chosen to run Alacritus specially tuned file system in place of its standard WAFL (Write Anywhere File Layout) file system, to optimize the performance of the VTL600. The file system NetApp inherited from Alacritus was built specifically to deal with the large sequential read and write requests commonly found in backup environments.

Another interesting facet of the VTL 600s file system is that it embeds metadata into each of its disk streams. As a result, if a head unit dies, an IT manager can plug the disk shelves into a new VTL600 to quickly rebuild its metadata repository.

/zimages/1/28571.gifNetApp virtual tape libraries look to ease backups. Click here to read more.

The VTL600s metadata repository is used to locate specific backup jobs with the virtual tape library.

The VTL600 hooks into a backup SAN (storage area network) using Fibre Channel ports on the head unit. After creating a virtual library using the VTL600s management tool, the Symantec/Veritas NetBackup 6.0 media management server with which we were testing was able to quickly locate the new VTL and write backup jobs to it.

The load-balancing intelligence built into the VTL600 automatically distributes the load from incoming backup streams to the four disk shelves. This is the first VTL system weve seen with this kind of load-balancing capability.

However, the VTL600 lacks data de-duplication capabilities such as those found in Avamars and Data Domains VTL products.

Senior Analyst Henry Baltazar can be reached at

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