Storage virtualization gets downsized
Pooling smaller storage networks is hot now, though a grander multivendor vision endures
- By John Moore
- May 30, 2005
Small is beautiful, claims the title of the classic 1973 economics text by E.F. Schumacher. The same might be said for storage virtualization. A couple of years ago, vendors discussed virtualization in sweeping terms. The objective was to take storage arrays from multiple vendors and present them as a unified, logical storage pool. Government deployments of virtualization technology, however, don't always conform to that ecumenical vision.
Virtualization in a single storage product, a concept as old as Redundant Arrays of Independent Disks (RAID), has become commonplace as more agencies adopt the technology. Installations may occur on a relatively small scale, as departments or remote locations seek improved storage efficiency.
But industry and storage managers have not abandoned virtualization as a multivendor solution. The number of products aiming to tackle this chore is growing, which some observers say represents true virtualization. Virtualization's benefits will have the greatest impact in large-scale, heterogeneous settings, they say. Those benefits include improved use of storage devices and ease of management.
"The big win for virtualization is where the customers have made very large investments and have really driven the complexity of their storage environments," said James Jackson, business development manager at iGov, a federal solutions provider.
However, size provides only one variable in virtualization's expanding scope (see "Many faces of virtualization," Page 30). Solutions can support Fibre Channel storage-area networks (SANs), Internet SCSI SANs or both. Virtualization also touches network-attached storage. Virtualization varies, but the primary solutions are based on hosts, arrays or networks.
Overall, virtualization is rapidly becoming a standard feature of storage solutions. "The industry leaders have already adopted storage virtualization and I would call it storage simplification into their shipping products," said Jay Brummett, chief technology officer for Ogden, Utah.
Virtualization in a box
Brummett said the city of Ogden exemplifies an organization that has grappled with islands of storage direct-attached storage, external RAID and other varieties. The city's storage devices were either significantly underutilized or nearly out of capacity. Overall, storage utilization was at about 50 percent, yet the city was running out of storage in some areas.
"The problem that I faced was that I never had the storage head space where I needed it," Brummett said.
Ogden responded by installing an IP-based SAN from LeftHand Networks. The 10-terabyte installation is a midsize SAN. It consists of Network Storage Modules, arrays that use Advanced Technology Attachment or Serial ATA drives.
The company's SAN/iQ software provides the virtualization element. SAN/iQ permits network administrators to configure the arrays as a virtual storage pool that they can manage through a centralized console.
Since deploying the new SAN, Ogden has improved storage utilization and left room to grow. "Currently, we manage our storage at a controlled 75 [percent] to 80 percent utilization," Brummett said.
LeftHand's brand of virtualization also simplifies administration. Brummett said adding storage into the SAN fabric is a matter of snapping an additional storage module into the architecture. Moreover, storage can be added or removed without disrupting users.
The Navy's Surface Combat Systems Center (SCSC) lab obtained similar results with a single-vendor virtualization solution. SCSC, based on Wallops Island, Va., tapped Xiotech's Magnitude 3D virtualized Fibre Channel SAN. The lab's main objective was flexibility.
The center tests shipboard systems before deploying them, evaluating up to six warship configurations daily. Before SCSC started using Xiotech's SAN, ship crews would arrive at the lab with disk drives bearing the configuration they needed. Some configurations required as many as 65 drives.
Les Martin, tactical systems engineer at SCSC, decided the media situation wasn't sustainable.
"You can never buy enough media, much less physically store it," said Martin, who describes SCSC as a small to midsize
He said the lab needed a storage solution that met the Navy's open architecture requirements and dynamically managed all the available storage.
Now, Xiotech's virtualization box can house the dozens
of possible shipboard configurations, Martin said. Drives contained in the Magnitude 3D arrays can be carved into virtual storage pools, or VDisks. The lab specifies a VDisk's capacity, and Magnitude 3D allocates unused blocks on each drive. To increase a VDisk's capacity, additional blocks are allocated. Each drive contributes the same amount of unused space, maximizing utilization.
"With storage virtualization, you use only the storage you need when you need it," Martin said.
The improved utilization helps the Navy avoid unnecessary hardware costs. Another benefit of virtual storage is that SCSC employees can change failed drives without sending for a vendor technician. That's an important consideration given SCSC's remote location on Virginia's Eastern Shore.
Some small to midsize organizations have migrated to a virtualized SAN from a hodgepodge of storage devices. But that may not be an option for larger enterprises running expensive storage arrays from more than one vendor. Those organizations seek virtualization to protect their storage investment and manage complexity.
Tools capable of pulling off this brand of virtualization represent a relatively recent development. "Some of this technology has only been around
for the last couple of years," said John Martien, senior system engineer at iGov. "Before then, you could not move from one vendor's array to another vendor's storage array and be able to move that data around."
Martien said iGov has standardized on IBM's SAN Volume Controller for multivendor virtualization. SAN Volume Controller can create a unified storage pool by tapping into IBM's arrays and those from EMC, Hewlett-Packard and Hitachi Data Systems, among others.
SAN Volume Controller, available since 2003, has been deployed at more than 1,000 customer sites, said Ron Riffe, an IBM storage software strategist. He noted a fairly good uptake of virtualization technology in the federal market.
SAN Volume Controller is an example of in-band virtualization, in which a hardware appliance resides in the data path between storage and servers. DataCore Software's SANsymphony and FalconStor Software's IPStor also fall into this appliance
Multivendor virtualization also takes place at the host, or server, level through products such as Veritas Software's Volume Manager, part of the company's Veritas Storage Foundation. Matt Fairbanks, director of product marketing for the company's storage and server management group, said one government virtualization customer has seen a 204 percent return on investment in three years and a 25 percent reduction in time spent on storage-management tasks.
Virtualization also occurs on the storage array itself, though this has traditionally been a single-vendor affair. But last September, Hitachi unveiled its TagmaStore Universal Storage Platform, which performs multivendor virtualization through
the array's storage controller.
The TagmaStore solution has completed virtualization testing with storage products from HP, IBM, Sun Microsystems and EMC, according to company officials.
HP and Sun are marketing TagmaStore products under their labels, said Dan Smith, enterprise technology consultant at GTSI.
Other recent virtualization developments focus on networks. Network Appliance debuted its V-Series line in March. It covers high-end and midrange arrays from Hitachi and IBM and HP's high-end products.
NetApp is working on support for EMC and midrange HP arrays, said Jeff Hornung, NetApp's vice president of enterprise file services and storage networking.
"Virtualization systems are only as good as the breadth you can virtualize," he said.
EMC entered the network storage virtualization space earlier this month with Invista. The product will initially run on intelligent SAN switches from Brocade Communications Systems and Cisco Systems. It will also operate on McData's intelligent SAN switch, which is slated for availability next year. Invista supports arrays from IBM, HP, Hitachi and Sun.
Dennis Hoffman, vice president of software marketing at EMC, said the company's virtualization approach lets the switch route data directly to storage for an out-of-band solution. He said out-of-band virtualization offers scalability and performance benefits. He said he has briefed two or three federal agencies in recent weeks on the technology.
Cisco, meanwhile, is helping EMC and other vendors push virtualization to the switch with its MDS 9000 Storage Services Module. EMC's Invista will ship on the module in the third quarter, according to Cisco officials. The module already ships with Veritas' Storage Foundation for Networks, which provides heterogeneous storage pooling.
Virtualization comes in various flavors. But the objective remains the same: Get the most out of storage resources.