Is server-less backup ready for prime time?


Despite the recent onslaught of announcements from various software vendors, server-less backup remains in its earliest stages. At best, products such as BakBone's NetVault, Computer Associates' Image Option for ArcServeIt, Legato's Celestra 1.1.2, Tivoli's server-less SANergy, and Veritas' NetBackup ServerFree Agent provide users with a glimpse of the technology's future "killer app" capabilities.

"The concept of server-less backup is a great one," says Robert Waldron, director of managed services at Articulent, a provider of storage management services in Hopkinton, MA. "But no one has a high-end pro-duct yet." High-end, robust im- plementations- capable of moving terabytes of data-are still 18 to 24 months out, he says.

This level of capability largely hinges on ironing out issues with the SCSI Extended Copy Command, which is being driven through the ANSI approval process by the Storage Networking Industry Association (SNIA). The command, which is based on code developed by Crossroads, Intelli-guard (now part of Legato), and Pathlight, is expected to become an industry standard for data movement. The code is embedded in a "data mover"-typically a bridge or router-which then moves data on behalf of a backup application (hence the term "third-party copy") directly from disk to tape.

The problem, explains Ron Riffe, director, product line strategy and management, at Tivoli, is that that level of capability is not ready. "SCSI Extended Copy is not something we would put into an alpha or a beta environment and certainly not into a customer production environment....It's just not cooked," he says.

Tivoli demonstrated SCSI Extend-ed Copy data movement at its Planet Tivoli event last spring, but says a retail product won't be available this year. Riffe points to unresolved issues with data availability, robustness, error handling, error recovery, replication, and performance, among others, as key stumbling blocks (see sidebar).

"It's not as fast [as backup over application servers], and there are already replication techniques available," Riffe explains. "These issues keep SCSI third-party copy from pervasive enterprise-wide use, and that's why we are not bringing it out."

Nevertheless, Tivoli continues to work with SNIA and the ANSI T10 committee to "build" robustness into the Extended Copy command, and with bridge/router vendors like Crossroads to maximize the performance of data-mover technology. "Ultimately, when we get it right, SCSI Extended Copy will allow for a lot greater parallelism to deal with very large data farms...where parallelism, not performance, will be the reward," says Riffe.

Similarly, Legato is working through issues with the Extended Copy command for the much- anticipated-and delinquent-release of a full-function Celestra product. Explains Scott McIntyre, the company's business line manager: "We are currently going through an analysis...to ensure server-less backup using Extended Copy will function optimally in large data-center environments." Like Riffe, he says these requirements center around configurability, manageability, and error handling with Extended Copy-enabled devices.

Meanwhile, recognizing the importance of getting some form of server-less capability out to end users, Tivoli has released an "application server-free" hardware implementation, which works with either EMC Symmetrix TimeFinder or IBM ESS FlashCopy, and "server-less SANergy integration," which makes use of technology acquired from Mercury Systems last year. Additionally, Tivoli will keep developing its LAN-free backup capabilities, which continue to outrun its implementations of SCSI Extended Copy.

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Ron Riffe

This article was originally published on January 01, 2001