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Computerworld - There's an age-old choice in IT -- whether to adopt a "best of breed" strategy for the power and flexibility it can bring, or go with a single vendor for accountability and simplicity. J. Craig Venter Institute Inc. (JCVI) believes in best of breed. The genomic research institute runs Linux, Unix, Windows and Mac OS in its data center. For storage, it draws on technology from EMC, NetApp, Isilon, DataDomain and Symantec.

"It's quite a heterogeneous environment," says computer systems manager Eddy Navarro. "Thankfully, we have a very talented staff here." (Learn how to build your own staff skilled in storage virtualization.)

And a talented staff was just what was needed to master the many flavors of storage virtualization, which can make multiple physical disks look like one big storage pool (For a detailed explainer on storage virtualization, check out our QuickStudy). Like JCVI, many organizations are enjoying the lower costs and added flexibility of storage virtualization. But the benefits can come with some headaches. Here, five IT managers who have led successful storage virtualization projects offer advice for relieving the pain.

Headache 1: Managing Multiple Vendors

For several years, JCVI had employed software-based virtualization in the form of Red Hat's Linux Logical Volume Manager, which allows logical partitions to span multiple disk drives. More recently, the not-for-profit research institute added hardware-based virtualization in the form of NetApp's V Series system to create a single virtual pool of storage consisting of EMC Symmetrix disks and legacy Clariion disks.

The Clariion drives, which came into the data center from a corporate merger, were being poorly utilized, Navarro says. Now, the NetApp V system reformats data going to and from the EMC disks, "and then you carry on just as if it's another NetApp system," Navarro says. That enabled JCVI to wring better performance from the legacy disks.

Each of JCVI's vendors makes its own unique contribution to a powerful and cost-effective storage architecture, Navarro says. But the diversity comes at a cost. "When you are talking about multiple vendors' hardware -- and they compete with each other -- it may not be the easiest thing to get support when something goes wrong," he says. "So you have to ensure compatibility first and foremost, and you have to know in advance something is going to work." (Read a guide to storage virtualization products.)

How to cope: Study the documentation, do your homework, and ensure that your approach has been tried before and is certified by the vendors, says Navarro. And if you don't have experienced technical staff, he adds, be prepared to hire some outside professional help.

Headache 2: Dealing With Extra Technology Layers

Even companies with less-complex environments report that although virtualization can ultimately simplify storage administration, putting it in place and tuning it is a demanding job.

Lifestyle Family Fitness, a rapidly growing chain of 60 health clubs based in St. Petersburg, Fla., is a Microsoft shop built around SQL Server and .Net development of Web applications. For storage virtualization, it uses IBM's SAN Volume Controller (SVC), disk arrays from IBM and EMC, and IBM Brocade SAN switches. IBM DS4700 disks provide 4Gbit/sec. Fibre Channel connections for the company's online transaction processing applications, while the Clariion drives handle less-demanding jobs like backups.

The IBM SVC was brought in to resolve an I/O bottleneck. The high-speed Fibre Channel drives and cache on the SVC appliance opened up the bottlenecks almost like an I/O engine would, says Mike Geis, director of IS operations. Moreover, the setup allowed Lifestyle Family Fitness to use its new IBM-based SAN while continuing to use its old EMC SAN. "In the past," he says, "you'd bring in a new SAN and have to unload the old one."

Geis says the SVC architecture promises vendor independence. He says he has a "great relationship" with IBM, but if that ever changed, he could easily bring in drives from another supplier and quickly attach them directly to his storage network. "We aren't held hostage by the vendor," he adds.

But the advantages come with some difficulties, Geis notes. "You are adding complexity to your environment. You add overhead, man-hours of labor, points of failure and so on. You have to decide if it's worth it."

How to cope: "Pick strong partners -- both vendors and implementation partners -- and make sure you are not their guinea pig," Geis advises.