When it comes to storage virtualizsation, everyone from the top vendors to enterprise users talks about it, but nobody does much about it.

That is, until now. The major storage companies are delivering products or planning to shortly, and the proof of the storage virtualisation concept is coming to a data centre near you.

Storage virtualisation is the ability of IT managers to work with logical representation of physical storage. Using virtualisation, IT managers can see and manage data as a single logical resource, regardless of where it physically resides in the typical disparate group of storage systems and networks. It should be noted that storage virtualisation has existed in the mainframe world for many years. Bringing it into the open systems arena, where multi-vendor systems and operating systems proliferate, has proven a bit more difficult.

The promise of storage virtualisation is cost savings, simplicity, and increased productivity. "For years, companies simply threw more storage at their storage problems, but now they've got a management problem. Virtualisation promises to make all that storage easier to manage because it won't matter where the data is stored," said Randy Kerns, an analyst at the Evaluator Group.

For years, that is all storage virtualisation was: promises. Granted, some smaller companies have offered storage virtualisation products, but now most of the major players have introduced products or laid out their storage virtualisation strategies. That means IT departments can begin to implement storage virtualisation projects, said Kerns. "I think we're going to see some results before long. It's not going to happen overnight. IT managers aren't going to completely replace their storage systems, but we'll see how this works before long," he said.

IBM and Hitachi Data Systems have introduced storage virtualisation products and EMC Corp. has shown its Storage Router offering. EMC says it plans to ship the Storage Router by the end of the second quarter. Last month, HDS unveiled multi-vendor virtualisation capabilities for its TagmaStore Universal Storage Platform, raising its profile in the storage virtualisation sweepstakes.

In or out
There is a key architectural difference between EMC's approach and that of IBM and HDS.

IBM's TotalStorage SAN Volume Controller is a controller that sits on the data path between applications and storage resources. EMC's Storage Router is out-of-band, with the router communicating with intelligent switches such as those from Cisco Systems Inc. to establish a connection, allowing the application and storage devices to communicate directly, said Mark Lewis, executive vice president for storage software at EMC. (We wrote more on this topic here.)

IBM argues that its system is much faster because it allows for caching near the application, said Jens Tiedemann,IBM's vice president of storage software."Our approach allows for companies to perform more services, such as copy services and data replication, over the network," he said. HDS's system is roughly similar to IBM's take on storage virtualisation.

Kerns said both vendors' approaches are viable, but that users will likely dip their toes in the virtualisation waters slowly. "I don't see too many storage managers going wholesale for virtualisation initially. It will take a while to build," he said.

Customer examples
One of the companies taking the dip is Oakwood Healthcare Inc., a network of four hospitals in southern Michigan. According to Brian Perlstein, the information technology technical architect at Oakwood, he has already seen some results.

Oakwood recently completed a mission-critical storage software implementation for its 16 Terabytes storage system. Working in concert with a solution provider, Logicalis Group, the organisation installed IBM's TotalStorage SAN Volume Controller storage virtualisation software. TotalStorage SAN Volume Controller software combines the capacity from multiple disk storage systems into a single storage pool, which is managed from a central point and enables changes to physical storage with minimal disruption to applications. It supports several non-IBM storage systems, including EMC, Hewlett-Packard Co., and Hitachi Data Systems.

"We felt we were under-utilising our storage infrastructure and that storage virtualisation software can help us create solutions that dramatically improve our utilisation by more than 30 percent as well as helping streamline our infrastructure," he said, speaking at a storage virtualisation presentation sponsored by IBM. "I have to say the combination of IBM's Storage virtualisation technologies did help us create a much more granular approach to managing storage devices. It has basically allowed us to create tiered storage solutions that can work across any hardware platform, and has certainly helped us with cost savings," Perlstein said.

Perlstein said Oakwood is currently in the midst of installing IBM's TotalStorage SAN File System that is part of an "infrastructure simplification programme," intended to make file and data management easier. The product accomplished this by providing tiered storage pools that are automatically managed.

Perlstein said that one benefit of storage virtualisation and its associated management software is that it maintains precise records of where the data resides, which he notes is a good thing to know with additional compliance regulations such as HIPAA.

Banking on virtualisation
Also jumping into the new world of storage virtualisation will be German bank Commerzbank AG, which plans to consolidate and simplify its existing storage infrastructure by installing 13 IBM TotalStorage DS8000disk storage systems connected through a Fibre Channel-based network using Brocade directors, and with IBM TotalStorage Productivity Center software to manage the system.

The bank will install more than 45TB of new storage disk space for backing up the bank's commercial banking, investment, and administrative data. As with the Oakwood project, the bank's goal is to improve the productivity of its storage systems. "As a result of the consolidation of our systems, we can enhance the agility in our customer channel and services offerings as well as improve the storage and access time to data," said Peter Kraemer, global head of IT production at Commerzbank.