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NTAP Disses VTL De-Dupe

Network Appliance is adding compression capabilities to the virtual tape library (VTL) platform it rolled out in February 2006 in an attempt to boost performance and capacity as demand for VTL heats up. (See NetApp Readies Virtual Tape.)

NetApps late to the party. Most of its competitors already offer features designed to improve VTL scalability, performance, and efficiency. However, NetApp's going against the grain by adding compression through hardware. Most of the vendor's VTL competitors have focused on increasing VTL performance by adding data de-duplication software.

Data Domain and Diligent Technologies, for instance, have offered VTLs with de-duplication for months. FalconStor, whose software runs on VTLs sold by EMC, IBM, and Sun, recently announced a de-duplication product. (See FalconStor Extends VTL and FalconStor Plots De-Dupe Debut.) So did VTL startup Sepaton. (See Sepaton Readies De-Dupe.) Quantum plans to offer de-duplication in its VTLs later this year. (See IBM Accelerates SOA Use.)

What’s the difference between de-duplication and compression? Compression algorithms reduce a file’s size by removing redundant data within that file. De-duplication eliminates redundant files spread across a storage system, saving one instance of each file. Both are features VTL vendors are offering to reduce the amount of data and increase the speed of backups.

However, de-duplication achieves a far greater compression ratio when it comes to reducing the load for the VTL. Most de-duplication suppliers claim to squeeze data at a ratio of 20 to 1. NetApp claims its compression can squeeze data by two or three times its normal capacity.