CA Introduces Serverless Backup Technology
Although we have come a long way from the days when networks had to be shut down for backup, the process can still be a problem for network performance, particularly in 24x7, high-availability systems. Computer Associates International Inc. (CA,
www.ca.com), however, may have taken the next step in smoothing backup procedures.
CA introduced a system where the storage server controls the backup process, but data is not moved through the server. Instead, the software exploits the Storage Networking Industry Association (SNIA, www.snia.com) extended copy command. The software on the server sends commands to the network hardware to begin moving data from the disk storage to tape backup.
The extended copy command is a part of a set of standards set forth by the SNIA. While the standards have been approved by the industry body and adopted by major vendors in the SAN space, they are still short of being a truly open standard: "Finalizing them is still a little on the horizon," says Peter Malcolm, senior vice president of storage management at CA. Extended copy is a variation on the SCSI move command, adapted for use on SANs.
SANs provide the resources to handle fast, flexible storage management away from the central parts of the network, allowing an array of storage resources to be combined into a single system. Early SAN systems required the data moving from primary storage to tape backup to go through the storage server, eating up a good deal of throughput.
While this was an improvement over systems where backup is only feasible at night or on weekends, enterprises that need maximum throughput at all times, such as e-commerce organizations, still suffered performance dips during backups. "Everybody wants their backup faster and faster," Malcolm says.
Dan Tanner, an analyst at the Aberdeen Group Inc. (www.aberdeen.com), has no doubt that the SNIA standards will gain wide adoption, eventually becoming an open standard. "A lot of hardware vendors are standardizing with SNIA standards," he says. While today’s, SAN market still has the air of proprietary competition, he feels storage will increasingly become standardized.
Users interested in enabling serverless backup on their current SANs may worry that it would require the replacement of a significant hardware investment. Not necessarily. Serverless backup could be as simple as upgrading a single switch to one compatible with extended copy. "We wanted to make it as simple as possible for people to deploy this product," Malcolm says. Switches, bridges, storage devices, and host/bus adapters all have the ability to bring serverless back up to SANs. Furthermore, Tanner suggests that newer hardware may already be compatible.
Tanner explains that serverless backup in one form was already available, with some serious limitations. Storage devices were capable of block-based input/ouput, unaware of individual files or content. Tanner says that "with the SCSI move command, its possible to move files, which adds file level intelligence." This has the potential to speed backups by saving only new or changed files, rather than entire blocks.