InformationWeek
Defining The Business Value Of Technology
|
July 24, 2000 |
 |
Serverless Storage Idea Takes Hold
From intelligent switches to outboard servers, companies try to free CPU as they save data
By Mitt Jones
 |
| Related links from our sister publications: |
|
|
 Send Us Your Feedback |
oo much data, too little downtime: For IT professionals, the challenge of efficiently backing up information gets more difficult each day, thanks to growing data repositories and to the increasingly common expectation that data be available around the clock. On top of that, it's assumed that backing up all this information shouldn't be a drag on application performance.Some systems administrators are finding relief by deploying Fibre Channel-based storage area networks, which can move live data and backup traffic off the LAN. But even with LAN-free backup, a problem persists: The server hosting the data being backed up must move the data to the tape library across the SAN, eating up CPU bandwidth that could otherwise be used by applications.
The solution may well be serverless backup, which shifts the responsibility for data movement from application servers to some other component on a storage network, such as an intelligent router or switch. That's just beginning to happen--products such as Computer Associates' ARCserve 2000 storage-management software, for example, can be paired with hardware such as CrossRoads Systems Inc.'s 4x50 line of storage routers to send data directly to an archiving device, bypassing the application server.
For companies that have already invested in a SAN, moving to serverless backup should reduce the load on application servers for a relatively small additional investment. Pricing for CA's ARCserve 2000 software, for instance, starts at about $700. For companies still contemplating a storage network, serverless backup may provide additional impetus. "Serverless backup is the killer SAN application," says Peter Malcolm, CA's director of development for storage management.
Mailmen Inc., a direct marketing services company in Hauppauge, N.Y., says that's on target. The company, a longtime ARCserve customer, has yet to deploy a SAN, but removing servers from the backup equation is a good reason to move faster on this front, says Ramon Abad, director of information. "One of our mailings can deal with 6 million addresses," Abad says. "I don't need the server dealing with the backup process for that."
NDS Health Information Systems, which maintains about 13 terabytes of pharmaceutical information it sells to pharmacies, hospitals, and manufacturers, says it installed a SAN specifically to deal with the problem of finding enough time to regularly backup data. "We knew we were going to get multiple data warehouses here, and we didn't want to keep replicating our backup solution, having a single backup on each one," says Neil Warner, NDS's director of technology. "We wanted an enterprise backup solution [where] we could have one console in our command center and one item to manage, and [one] that's able to take all the data and get us one repository."
NDS uses a system that's serverless from one point of view only--it relieves the load on the application server by requiring a dedicated backup server, or outboard server. NDS relies on a backup system from EMC Corp. called EMC Data Manager. While EMC says it's planning to deliver a fully serverless backup solution comparable to CA's offering soon, it won't disclose details.
In the meantime, EMC Data Manager, which works across a SAN or a direct connection, requires a dedicated backup server to move information from its Symmetrix storage systems to an archiving device.
While Warner says that NDS is happy with its current setup, the idea of a completely serverless backup on the SAN is intriguing. If EMC comes out with an offering that eliminates the dedicated backup server, Warner says, "we definitely would look at it."
Most vendors interested in serverless backup are building their products around the extended copy command specification proposed by the Storage Networking Industry Association. This command is largely based on storage management vendor Legato Systems Inc.'s Celestra copy command. The Celestra Consortium was formed by Legato and more than 30 other hardware and software vendors, including Advanced Digital Information, CA, and Compaq, to bolster industry support for serverless backup through the extended copy feature.
SCSI specifications have long included a copy command to allow one SCSI device to move data directly to another, assuming both exist on the same SCSI bus. But the extended copy command, referred to by some vendors as the third-party copy command, allows data to be moved between storage devices across different buses.
A device called the copy manager is paired with software that supports the extended copy command and actually moves the data from one device to the other. This copy-manager functionality might be provided by a tape library, a bridge, a switch, a router, or any of a number of other components on the storage network--including a dedicated backup server.
The point to remember for serverless backup is that a component other than the application server is responsible for the cycle-intensive chore of moving the data. The payoff for companies that implement serverless backup will be very low drag on the application server during the backup process--typically, as low as 2% instead of 25%, according to CA's Malcolm.
Storage components that support the extended copy command are available (or will soon be) from Advanced Digital Information, Crossroads Systems, Gadzoox Networks, Pathlight Technology, Vicom Systems, and others. "Vendors are just starting to roll out their initial versions," says Gartner Group's Mark Nicolett, research director for software infrastructure. "These are the early days of the technology."
continued...page 2
Illustration by Joel Nakamura
Photo by Edward Santalone
Back to This Week's Issue
Send Us Your Feedback
Top of the Page
Featured Microsite
