Disk-to-disk backup appliance vendor Revinetix updated the RevOS software on its dedicated backup appliances to store just a single copy of a file or e-mail message across multiple locations and backup sessions. Their PR folks then sent out a press release saying they were adding data deduplication. The semanticist in me says "That's not deduplication, that's single-instance storage." I reserve the term deduplication for processes that reduce duplicate data contained in similar, not just identical, files or other objects.Which is not to say that integrating single-instance storage into an existing backup application isn't a significant accomplishment. Revinetix's Volo desktop and Setio rack mount appliances run RevOS, which serves as both operating system and backup application with system administration through a Web-based GUI. Revinetix's single instancing runs as a post-backup process and can identify single-instance files with the same contents even if they don't have the same name.

Most backup solutions in the SME market where Revinetix plays compress data, at best, which should let a user running Revinetix's system protect 10% to 30% more stored data since duplicate files, like OS files, are stored just once.

RevOS runs backup agents for Windows, Macintosh, Linux, NetWare, and Unix servers. The Windows agent is a VSS requester and Revinetix has application agents for Exchange and SQL server. It even has a bare-metal restore image option.

Unfortunately, RevOS can only single-instance Exchange data if you make MAPI mailbox, sometimes called brick level, backups that are always the slow and cranky way to backup Exchange.

Most dedicated backup-to-disk solutions for the SME market ignore the need for removable storage for long-term archival storage or off-site safety. RevOS can spool files and/or backup sets off to one of a Setio's hot-swappable drives or the now ubiquitous USB drives and, as any off-site solution must in this day and age, encrypt the archive disk.

Prices start at $2,600 for a 250-GB Volo. A Setio rack mount unit with four 1-TB drives will set you back $13,995. One with 16 1-Tb disks is about 50 grand.