Switching to a new storage model
- By John Moore
- Sep 13, 2004
In the Fibre Channel world, storage applications typically run on servers or disk arrays but not in the network fabric. Some storage vendors seek to shift this balance of application power by placing key applications on Fibre Channel switches.
Proponents believe moving applications to switches will improve storage
management, facilitate multivendor storage environments and ease tasks such as data migration. Mirroring and volume management are among the other storage chores that could benefit from a fabric existence.
But drawbacks accompany the advantages, not the least of which is the cost of intelligent switching environments. The price tag can be six figures, depending on the size of the switch and resident applications. Some customers may find it more cost-effective to run storage applications on servers or arrays, some observers said.
Most government customers aren't yet clamoring for switch-based applications. But expanded education efforts may place the technology on more federal radar screens. The greater participation of big-name storage and networking players also will improve the emerging technology's visibility, according to industry executives.
In that regard, Cisco Systems Inc. already sells storage applications for its MDS 9000 switch family. Officials from Brocade Communications Systems Inc. and McData Corp., meanwhile, plan to bundle storage applications on their switches during 2005. That's the year many observers believe the switch-based application market will begin to heat up. Once it does, they don't expect government customers to remain on the sidelines for long.
"They are looking at the technology now and evaluating it," said Jay Kidd, chief technology officer at Brocade. "They won't wait for commercial [customers] to prove it out. They will be just as aggressive."
The switch is on
That motivation will stem from the opportunity to reduce expenses, some vendors said. Organizations that put storage applications on the network can avoid the cost of purchasing vendor-specific software for arrays or volume management software for host computers, said Rick Walsworth, vice president of marketing at Maranti Inc. The company sells a network storage controller, offering storage services such as volume copy, virtualization, mirroring and replication.
Walsworth cited replication as one area that can yield savings. "Network-based storage services enable the ability to replicate between heterogeneous storage arrays at a fraction of the cost of proprietary solutions," he said.
That ability to span mixed storage settings — whether for replication or other purposes — is another plus for smart fabrics. Some customers seek to avoid the necessity of using multiple proprietary applications from various array vendors to manage their storage shops.
"We've been looking into putting more intelligence into the fabric for some time now," said Glenn Exline, manager of advanced technology at Computer Sciences Raytheon, a contractor that supports the Air Force Space Command's 45th Space Wing. The ability to run applications on a switch, he said, "allows you to be a lot more vendor-agnostic."
Specifically, officials from the 45th Space Wing seek the ability to allocate storage attached to virtual tape libraries without having to "worry about what vendor is at the end of the query," Exline said. The organization already has brought in Alacritus Software's virtual tape library technology. Officials from the 45th Space Wing plan to eventually install Brocade's SilkWorm Fabric Application Platform, a switching
platform that will support fabric-based
Improved management is another advantage of fabric-based applications — and one that could reduce operating costs. By moving storage applications to a handful of switches vs. a multitude of servers or arrays, organizations can reduce the number of management touch points, thus saving administrative time and money.
Switch-based applications let organizations "consolidate volume management into a smaller number of points in the fabric," Kidd said.
In an enterprise environment, that may mean "being able to manage a switch environment for storage needs as opposed to hundreds of disparate servers," said Mark Thoreson, director of technical sales at solution provider AC Technology Inc.
Neal Czaplewski, enterprise sales manager for CDW Government Inc., said he views management efficiency as a major source of return on investment. "By moving applications to the fabric, administrators can standardize their environments on a single management platform and no longer have to perform these functions on each specific array," he said. Administrators can thus "consolidate management functions and streamline otherwise repetitive tasks."
But if management gets a boost, so does application performance. Storage applications such as data migration are expected to run much better in the fabric. Kidd said data migration could be the first killer application for fabrics.
Traditionally, there are two options for data migration. One involves copying the data while the application is running, then shutting down the application, doing a final sync on the data, reconfiguring the server to see the new data location, and restarting, Kidd said. The other approach focuses on shutting down the application, copying the data, reconfiguring the server, and restarting.
But organizations with fabric-based applications can avoid migration headaches and application outages, proponents said. Performing data migration in the fabric, Kidd said, lets the server see a fixed location for data, and the fabric-based application can "move the data behind the scenes."
But before agencies make the switch, they should consider potential drawbacks.
Running applications on the switch could also create vulnerability. Organizations with a single point of storage management could end up introducing a single point of failure, CDW-G's Czaplewski said.
Vendors are aware of this potential pitfall. Walsworth said Maranti builds redundancy into its CoreSTOR products. The chassis features redundant internal cooling fans, system controller cards, power supplies and crossbar fabric cards, for example. In the event of an emergency, the product offers the ability to switch from a production storage controller to a standby machine.
Czaplewski noted that interoperability among different switch manufacturers could also be an issue. An agency running a mirroring application in the fabric may have to employ the same switch vendor in both the production and target environments. But that concern could diminish as vendors such as EMC Corp. introduce application-specific integrated circuit-based applications capable of residing on multiple switching platforms, Czaplewski added.
Cost is another inhibitor. Customers, Czaplewski said, "are going to need to examine the cost of deploying this type of technology." The return on investment may be favorable for a customer that previously lacked the ability to perform mirroring and other storage management functions. But the assessment becomes more difficult if an organization already has deployed mirroring and replication capabilities elsewhere, he added.
In certain storage environments, other storage approaches may be easier on the budget. That's the case for a homogeneous storage environment, in which storage devices play well together, said Mark Delsman, vice president of business strategy at Adaptec Inc., which markets Fibre Channel arrays. "It's a more cost-effective solution to run those storage applications on the array instead of a switch," he said.
He added that a switch-based approach makes more sense in a mixed storage
Indeed, Walsworth defined a typical candidate as having more than 10 terabytes of heterogeneous storage-area network data and experiencing more than 20 percent year-over-year storage growth.
Czaplewski mentioned another criterion: "The key is whether or not your business objectives are being met by moving the [application or applications] to the fabric," he said.
Moore is a freelance writer based in Syracuse, N.Y.