PHOENIX -- Virtualization sounds great in theory, but how do you actually do it, and what are some of the pitfalls...
to look out for?
In today's always-on environment, finding the opportunity to test out new technology without disrupting production systems is hard to do. At this year's Storage Networking World, the Storage Networking Industry Association held a series of three-hour classes for users to try out virtualization, free from the constraints of the office.
"We've had IBM's SAN Volume Controller for four months, but I haven't had time to unwrap it yet … Here, I can get some intuitive knowledge on what to do with it when we finally open it up," said Laurence Whittaker, enterprise storage manager for Hudson's Bay Co.
Similarly, Mike Harvey, systems engineer for Ardent Health Services, used the opportunity to learn more about the technology before deciding what to buy. "You don't usually get hands-on experience until you've signed a purchase order," he said.
In groups of two or three, with a maximum of eight people in a class, users gathered around a monitor and laptop with printouts on how to operate the technology. Instructors stood by to help out if needed.
Each group was given a choice of three virtualization technologies: Maranti Networks Inc.'s CoreStor 3000; Sun Microsystems Inc.'s 6920; or a Network Appliance Inc. V-Series.
These products and the back-end storage being virtualized -- including an EMC Corp. DMX 1000, Hitachi Data Systems (HDS) TagmaStore, IBM Shark and Sun Microsytems Inc. SE9990 and SE6136 -- were all running in the interoperability demo in the exhibit hall, connected to the lab.
Users set about discovering disks, creating virtual logical number units (LUNs), discovering initiators, provisioning virtual LUNs and finally dynamically expanding LUNs. In a nutshell, virtualization makes physical storage devices act and appear as logical volumes in a SAN. Storage administrators can then allocate the volumes on demand to application servers without resorting to complicated host zoning and LUN mapping procedures.
Stefan Schneider, storage manager at Helsana Versichweungen AG, has two HDS arrays and some older storage and can't move data between them. "I am hoping virtualization will help with that," he said. However, after testing the technology for the first time, he was a little apprehensive about it. "It worked, but I am not sure why, as I couldn't see what was going on … and I am also unclear if there is a path back from virtualization if we decide we want to get out of it," he said.
Another interesting question that arose during the session concerned the affect on performance when virtualizing disks of different speeds. "If you mix up disks where the seek time is faster on one than another, you lose performance," said Ardent Health Services' Harvey. The vendors agreed this could be a problem in highly performance-sensitive environments.
Outside the lab, many users said they feel virtualization is still a long way off. "There still isn't a clear definition of what it is or where it should happen … it is way too early in the game for us," said David Bronder, systems and platform administration at The University of Iowa.
For others, it's too expensive. Evan Davis, vice president of systems support at Teleperformance USA, is in the middle of migrating off DAS to a Hewlett-Packard Co. EVA 5000 SAN, while also undergoing a major server consolidation project. "Virtualization would probably help us with this, but in the call center business we have to watch every cent, and at the management level they don't see IT as strategic," he said.
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