BREAKING SHACKLES

It also allows an organisation to avoid vendor lock-in. The data storage industry is infamous for its heterogeneity and has sprawled in many proprietary directions. While industry bodies such as the Storage Networking Industry Association (SNIA) are making some efforts to introduce open standards, organisations often find themselves locked in to the products of single vendors.

An abstraction layer that allows for ubiquitous access to the storage capacity of all of these different vendor products is seen as a means of avoiding such limiting scenarios.

"Virtualisation enables you to manage many different storage products on one console," IBM storage business unit executive, Francois Vazille, said. "It gives you flexibility in which disk hardware you want to use."

In its ideal form, the complexity of the storage environment is also transparent to the user. "All the user might notice is a small amount of extra time to access that data," Symantec's Read said.

While there is little argument over the benefits of virtualising storage resources, there is a good deal of conjecture in the market as to where in particular the technology should be deployed. Host-based virtualisation sees the abstraction layer deployed on the server, network-based virtualisation sees it deployed in the switch, while array-based virtualisation sees the technology limited to the storage device itself.

Proponents of host-based virtualisation argue that it is the best way to effectively virtualise storage resources across multiple hardware platforms. "You have the freedom to swap and change hardware," Read said.

As larger organisations increasingly deploy Storage Area Networks (SANs) to manage their resources, networking vendors such as Brocade argue the technology should be deployed in the switch.

"Specifically compared to host-based solutions, consolidating storage virtualisation functions in the storage network can greatly reduce the instances and versions of software that need to be deployed and managed," Brocade product marketing manager, Mario Blandini, said. "Rather than managing multiple versions of software across many server touch points and multiple operating systems, switch-based applications enable central management of a single application version.

"Centralisation makes management easier, and also provides increased capabilities in that any server with a SAN connection can use the virtualisation services, not just the operating systems for which the host-based software is available."