By Heidi Biggar
Despite a strong push by nearly a dozen vendors to promote the technology and an almost year-long media/analyst campaign to educate users about its varied benefits, storage virtualization has yet to gain a solid footing in the IT community.
"The main barrier to adoption is user understanding and acceptance," explains Jacob Farmer, chief technology officer at Boston-based Cambridge Computer Services, an IT consulting firm specializing in data storage and related technologies. "Virtualization is in many ways a superior technology to monolithic storage arrays, but it's unfamiliar...and in today's economy no one wants to get fired for making a bad decision."
However, few end users have implemented virtualization, even though analysts say that nearly 100% of all storage area network (SAN) implementers can potentially benefit from virtualizing their storage network environments. Analysts point to the slowing economy, high cost, user confusion, and vendor-induced hype as factors contributing to the technology's low adoption rate.
Vendors that sell storage virtualization products include Compaq, DataCore Software, DataDirect Networks, FalconStor, IBM/Tivoli, StoreAge, StorageApps (now part of Hewlett-Packard), Veritas Software, Vicom, and XIOtech. Others vendors such as McData are working on virtualization at the SAN fabric level, and a variety of vendors offer products to virtualize disk or tape environments.
Of the 608 people surveyed in a recent InfoStor poll, 210 said they planned to purchase storage virtualization products in the first half of 2002.
None of Cambridge Computer's customers, for example, have asked specifically for SAN virtualization. They have described storage needs (e.g., LUN masking, data pooling, load balancing, heterogeneous operating system, and subsystem support) that can be addressed by virtualization products, "but they simply did not know to ask for virtualization by name," says Farmer.
Ironically, attempts to promote storage virtualization-a technology designed to mask the complexity of storage networking-have actually increased user confusion and expectations about its potential applications and benefits.
This is typical of many new technologies, explains Tom Clark in his recent book, IP SANs: A Guide to iSCSI, iFCP, and FCIP Protocols for Storage Area Networks (Addison-Wesley, 2002): "The introduction of a new technology is followed by a sudden ramp in customer expectations, driven by vendors who are eager to gain mind share and who consequently may exaggerate product capabilities and availability." (Clark is also director of technical marketing at Nishan Systems.)
But despite its current immaturity, storage virtualization is expected to play a key role going forward. "It is one of two prerequisites for ubiquitous storage access," says Clark. "The other is a common universally available network infrastructure."
Among other advantages, virtualization provides users with an unprecedented level of investment protection. New storage technologies (e.g., subsystems, hosts, and interfaces) can be easily integrated into the existing architecture and scaled as needed. And, as features are automated, virtualization is expected to drastically ease the management of storage networks.
Industry experts expect much of the hype surrounding virtualization to diminish this year and for the technology to gain significant traction in the end-user community. This, along with the emergence of new technologies such as IP SANs, should help move virtualization along the new-technology hype curve (see figure). According to Clark, IP SANs will facilitate the integration of network-attached storage (NAS), SAN, disk, tape, and virtualization onto a common infrastructure.
Nobody says that hiding the complexity of storage management via virtualization will make complexity disappear. "It just shifts the burden from intelligent human beings to intelligent products," says Clark. "We'll get there eventually, but the technology is still in its infancy."
At this early stage of adoption, few surveys have been conducted about virtualization usage. However, based on interviews with early adopters (see sidebar), in general,
- Current installations are fairly low end, and often include support for multiple operating systems but rarely multiple vendors' disk subsystems. Disk capacity varies but is typically in the multi-terabyte range;
- The most common benefits of virtualization are support for multiple operating systems and data pooling/sharing; and
- The trend is to house disk and virtualization intelligence in the same cabinet (vs. stand-alone systems) and to buy new disk systems to go along with the virtualization capability.
Virtualization benefits: Case studies
By Heidi Biggar
DAYTONA BEACH COMMUNITY COLLEGE
Like most early adopters, Mike Burke, director of information services at Daytona Beach Community College, had no idea that virtualization would play a key role in his storage area network (SAN) architecture. He simply knew that he needed 1TB to 2TB of dynamically configurable disk capacity and support for multiple operating systems (HP-UX, Windows NT, and NetWare), and that he didn't want any network-attached storage (NAS). He also had to keep the total cost of the SAN under $800,000.
However, none of the disk array vendors he consulted (Compaq, Dell, EMC, Hewlett-Packard, and StorageTek) could meet those requirements. The greatest challenge, he discovered, wouldn't be price or capacity, but supporting the college's Unix, Netware, and NT systems with a single disk platform.
"What I had envisioned was a disk subsystem that we could plug just about any operating system into and then allocate capacity as required," explains Burke. "But no vendor could do it alone."
The answer, Burke would discover, was virtualization. StorageTek (the college's primary disk array supplier) brought in Navi Stor, a storage and backup integrator in Concord, MA, which recommended DataCore's SANsymphony virtualization software. The software and other key SAN components were bundled into a single cabinet.
The school's SAN/virtualization system has been up and running for more than a year. Burke reports no problems.
at a glance...
User: Daytona Beach Community College
- Virtualization: DataCore SANsymphony software (two storage domain servers)
- Disk array: STK 9176 with dual controllers, RAID-5, 1TB capacity
- Support for multiple operating systems
- Ability to add/remove storage on-the-fly
- Lower management costs
- Improved performance
COST (SAN/virtualization): $700K
PROS REVENUE MANAGEMENT
Like Daytona Beach Community College, PROS Revenue Management, a provider of pricing and revenue optimizing software in Houston, was turned on to storage area network (SAN) virtualization by a third party-and like the community college, its primary concern was multiple operating-system support.
"Dell got us in touch with StorageApps because they couldn't help us on the Unix side of the house with our Clariion disk system," says Jeff Wannamaker, vice president of technical services at PROS.
Wannamaker says the company's development efforts hinge on its ability to support multiple operating systems. "Our code is written on NT, but then ported [in the form of test databases] to various client platforms, so that requires us to run just about every operating-system flavor," he explains.
StorageApps' SANLink not only provided PROS with broad operating system support, but it also made moving disk capacity around the network easier and improved capacity usage. Also, when it came time to add more disk capacity (an Hitachi disk array), PROS wasn't restricted to EMC Clariion subsystems. Wannamaker says he refreshes his disk technology every 18 to 24 months.
Though he implemented the storage network and virtualization capability simultaneously in January 2001, Wannamaker says he didn't start making full use of the virtualization piece until six months ago, when he added the second disk array.
at a glance...
User: PROS Revenue Management
- Virtualization: StorageApps SANLink
- Disk arrays: EMC Clariion and Hitachi (5TB each)
- Support for multiple operating systems
- Ability to move storage on-the-fly
- Improved disk usage
- Lower management costs
COST (SAN/virtualization): $800K
One might argue that what Storage Access, a managed storage service provider based in Miami, is doing with FalconStor Software's IPstor is more about IP connectivity than it is about storage area network (SAN) virtualization, or is it?
Explains Paul Sasche, Storage Access president and CEO: "IPstor allows us to take a common pool of Fibre Channel storage [serving multiple operating systems] and carve that pool up to many types of hosts...and then allocate and 'virtualize' that storage to users over IP networks." Currently, Storage Access doesn't take advantage of IPstor's support for heterogeneous disk subsystems.
On the Fibre Channel side, Storage Access also uses Vicom's router-based virtualization products. "We use it for virtualization within the data center and for replicating data from one storage system to another," says Sasche.
"Essentially, we abstract the hardware limitations and functionality from the customer and provide the storage they need in the sizes they need it," Sasche explains. "This allows us to allocate storage without being bound by the limitations of a storage controller." He adds that the right switch/controller combination could achieve some of the same benefits.