VTLs, which are disk-based systems that emulate tape systems while offering higher performance, have two main markets, said Krish Padmanabhan, general manager of the Heterogeneous Data Protection Business Unit at NetApp. At the departmental level, users are primarily concerned about replacing tapes, while at the enterprise level, the focus is primarily on performance, he said.

Typically data compression can result in a 50 percent improvement in performance by reducing the amount of data that needs to be saved, Padmanabhan said. However, the amount of compression depends on the type of file, he added. For example, JPEG files typically don't compress at all, while Microsoft Office documents can be compressed to a tenth of their size, he said.

Offering data compression in hardware results in better performance than doing the data compression in software, Padmanabhan said.

The NearStore VTL300 is an entry -level system with a capacity of 53TB with compression and a sustained write speed of 500 MB/sec. The NearStore VTL700 has a capacity of 128TB with compression and a sustained write speed of 850 MB/s. The NearStore VTL1400 is a dual-head system with a capacity of 256TB with compression and a sustained write speed of 1700MB/sec. Users of the first two models can upgrade to higher models, Padmanabhan said.

The Sunnyvale, Calif.-based company, which began shipping VTL products in February that did not have data compression, had said in April that it would be adding data compression to its VTL products in about a year (see http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=110931).