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HP Signs On For ProStor’s RDX Disk Cartridge

Tape vendors have been having a hard time lately and nowhere worse than in the SMB market. In the 1990s, small businesses backed up to DDS/DAT tapes. But as the 20 GB (native) capacity of DDS4 became too small for even SMB full backups, no clear replacement emerged. ProStor System's proposing its RDX hard disk in a cartridge system as a good alternative and HP's jumped on the bandwagon, offering RDX docks in Proliant servers and XW workstations along with 160-GB and 320-GB HP-branded cartridges.

While using removable hard drives to replace tape isn't a new idea, RDX represents the engineer's approach to the problem. Where some competitors use hot-swap disk caddies designed for servers or security applications, ProStor's built an admirable system. First, sacrificing some capacity and performance for reliability, it uses laptop-style 2.5-inch disk drives, which have built-in accelerometers, head ramp unloading, and other features that make them much more tolerant of shock and vibration than their 3.5-inch counterparts. They mount them into sealed cartridges, with additional shock mounting and a connector designed for large numbers of insertions and removals.

The cartridge is inserted into an external USB or internal SATA dock that locks the cartridge in place under software control so the user can't remove a cartridge that's being written to or has data in cache. Backup programs eject cartridges like they do tapes from a tape drive.

I can see a lot of advantages to RDX over a tape system for an SMB. First, they could require somewhat less care and feeding. Hard drives don't wear out as fast as tapes do, so an RDX cartridge may outlast a few tapes and the RDX doc, unlike a tape drive, doesn't need periodic head cleanings. Since SMBs rarely pay attention to the alerts from their backup software that the tape is bad or the drive needs cleaning, this should boost the backup success rate.

Like all backup-to-disk solutions, RDX also eliminates tape seeking and other delays during the single-file restores that are the most frequently needed.

The only thing I don't like is the cost. RDX cartridges cost 5-10X what the equivalent tape cartridge costs. This is balanced, in part, by the low cost of the RDX doc which, when sold with a cartridge, usually costs less than $150 more than the cartridge alone. My problem is the high cost of high-capacity RDX cartridges. I found a 160-GB cartridge online for $213. The drive inside was around $100, so the premium for the RDX cartridge was about $100. For the 320-GB cartridge, the difference was $200. I think a $100 premium is about right. After all, ProStor and the reseller have to make a buck. But since the costs for putting a cartridge around a drive are all fixed per drive, not per gigabye, costs, I don't understand why the larger cartridges cost so much more.

I'm sure someone from ProStor will let me know and I'll pass that on to you, my loyal readers.

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