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Call it what you will, but the DX30 bears a striking resemblance to virtual tape products - the likes of StorageTek's Virtual Storage Manager and IBM's Virtual Tape System. Like its MVS-focused cousins, the DX30 is essentially a large disk array coupled with software that emulates a tape drive.
Why does the DX30 emulate a tape drive rather than present itself as straight disk?
Not because backup software doesn't support backup to disk, says Michael Adams, Veritas product marketing manager for NetBackup. "Most backup and recovery products work with disk or tape, and have done so for a number of years," he says.
Rather, backup arrays emulate tape to make it easy to slip them into existing backup environments, and take advantage of disk's faster speed. Theoretically, you then get quicker backup and restore, as well as more successful backups. Tape remains in the equation for long-term archival purposes.
Virtual tape is fairly well established in the mainframe world. According to StorageTek's Steve Aaker, product marketing manager for VSM, the company has installed VSM at over 1,700 sites since the product was introduced in 1998, largely by organizations looking to reduce the floor space consumed by underutilized tape drives.
Meanwhile, the open systems space has little - if no
This spring, Quantum and partners Atempo, Legato, QLogic, Network Appliance, and OTG founded the Enhanced Backup Solutions Initiative. In addition to supporting one another's products in a virtual tape environment, the group will also attempt to educate potential customers about the benefits of inserting disk into the backup equation.
At the same time, French virtual tape software vendor NearTek announced its second generation Virtual Storage Engine, VSE2, which in addition to supporting mainframe operating systems, adds support for Unix, Linux and Windows NT, as well as open systems tape formats such as LTO and DLT.
StorageTek is also reportedly looking into porting its VSM to open systems, and Aaker suspects IBM is doing the same, "although they haven't invited me to Tucson [IBM Storage Systems Division headquarters] to take a look."
Of course, not everyone sees tape-emulating backup arrays as a good thing. Nexsan Technologies, which makes the ATAboy IDE RAID array, markets its device as a backup device, but forgoes the tape emulation approach.
If part of your interest in a backup array is to have an online, easily recoverable version of a file, a tape emulation device isn't for you, explains Diamond Lauffin, Nexsan senior executive vice president. That's because without the backup software, you can't restore the file.
Ultimately, immediate online access is what everyone is after. "The only reason you wouldn't do it is because you can't afford it," Lauffin says.
This was first published in July 2002