Backup for Small Business: Exabyte VXA-2

By Nick Stam  |  Posted 2003-12-05 Print this article Print

Who says tape drives can't be sexy? Most everybody, according to this PC Magazine review. But the Exabyte VXA-2 is worth a look for reliable small business backup.

Lets get this out of the way first: Small- and midsize businesses need to have a regular backup routine for their servers. Copying a few key files to a CD every now and then wont cut it if your servers hard drive crashes, and the days of downtime and thousands of dollars youll burn as a recovery service tries (perhaps unsuccessfully) to resurrect your data will be an expensive lesson indeed.

Even with the decreasing cost of hard drives, which lets you put a second drive in a server to act as a backup, tape remains the storage medium of choice for businesses with moderate-to-large volumes of frequently changing data. Unlike mirrored drives, copies of data stored on tape can be easily kept off-site for added protection.

One of the newest midrange tape solutions is the Exabyte VXA-2. A proprietary technology, VXA-2 is a good replacement for the aging DDS tape technology, which appears to have reached its limits on capacity (36GB native, 72GB with compression per cartridge) and performance (210MB to 420MB per minute). VXA-2 can store up to 80GB (160GB compressed) per cartridge, and it reads and writes data at 360MB to 720MB per minute. If thats still not enough capacity or performance for your needs, youll want to consider the higher-speed (and pricier) LTO, AIT-3, and SDLT tape technologies (see "Tape It to the Limit," March 11).

VXA-2 is unlike any other tape technology in that it reads and writes data on a packet basis rather than reading and writing large blocks of data along linear or helical tracks. VXA-2 drives can also adjust tape speed to match the transfer rate of the host. This avoids back-hitching operations that can occur with other tape technologies when data flow is interrupted and the tape is forced to stop, back up, and restart. Back-hitching not only decreases performance but can also accelerate media wear.

With VXA-2 technology, two head pairs (each pair containing one read and one write head, totaling four heads) are contained on a rotating drum and are arranged as leading and trailing pairs. The heads sweep across the width of the moving tape at an angle. (See for animations that describe the drives operation.)

During a read operation, all four heads perform read operations, with the leading head of a pair reading the data and the trailing head verifying it. During writes, the leading head writes and trailing head verifies.

To read the full story, click here.
Nick Stam Co-Founder, ExtremeTech
Ex-Director, PC Magazine Labs

Nick is a founder of the ExtremeTech website. He worked with co-founder Bill Machrone designing the site, staffing up, and getting initial content developed for ET's formal launch on June 12, 2001. Nick was Senior Technical Director of ET until mid-2003, while concurrently performing duties in PC Magazine Labs.

Nick was a technical director in PC Labs from late 1991 through mid-2002, and was Lab Director from mid-2002 until March 2005. Prior to PC Magazine, Nick was in the computer industry in various development, systems engineering, and management roles since mid-1980, and he received an MS in Computer Science from SUNY Binghamton.

In March 2005, Nick decided it was time to leave Ziff Davis Media (parent of PC Magazine and ExtremeTech) to pursue other opportunities, but wishes all the best to the ET and PC Magazine staff and reader communities!

Nick can be contacted at


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