Using technology from its acquisition of Decru, NetApp has included data encryption in NearStore, with a choice of encrypting the data before it is written to the virtual tape library (VTL) or prior to it being written to tape. Its Tape Smart Sizing capability provides the ability to take a sample of back-up data and estimate the compression ratio before writing to the tape library, so that maximum utilization is achieved on physical tapes.
Another feature is Self-tuning Performance, which balances back-up streams dynamically as the workload changes. Although not all of these features are unique, they are nevertheless functions that one would expect to be included in a product of this nature.
Still, NetApp looks set to succeed in the VTL market space, where it will provide stiff competition for EMC.
There are many VTL products on the market, with an increasing number of organizations opting to retain higher volumes of data on disk. The reasons for this are varied, but important drivers include compliance, the risk of litigation and the need to discover information rapidly, and the ability to recover individual lost or corrupt files speedily for end-users.
It is as a result of many high-profile litigation cases where companies have been fined because of an inability to discover files retained on back-up tapes, that many organizations are adopting a virtual tape library. However, this is not viable for long-term storage and is not what this technology was designed for.
The value of a VTL lies in its ability to provide a middle tier in a tiered storage architecture. Its strength is that it provides a medium-term storage solution for information that needs to be accessed on an infrequent basis, in situations where there is little justification in retaining it on the live system, but archiving it to tape would result in several access requests.
This technology is also deployed as a staging medium, providing rapid back-ups to disk using snapshots, for organizations where there is only a short back-up window or no back-up window at all, and then enabling the data in the VTL to be transferred to tape at leisure.
There is clearly a need and a value in VTLs, but as support for tape and not a replacement. Tape is still needed for long-term storage, but the tape vendors must develop better indexing techniques to allow the rapid location of information requested for litigation or by regulators.
Source: OpinionWire by Butler Group (www.butlergroup.com)
