Why virtualization services are necessary

Computerworld - Q: I saw you speak at a Brocade event in Washington last week where you discussed an overall "enterprise infrastructure virtualization" strategy. During your talk, you quickly (there wasn't enough time, by the way) discussed "services." Can you elaborate on what virtualization services are? -- P.B., Annapolis, MD

A: Sure. And you are right, there was too much stuff to cover and not enough time. We live and learn. I'll be doing more at an event in Chicago on June 21 if you just can't get enough!

A virtual "service" is an application that executes a specific function at one of the layers of abstraction within your infrastructure. Think of your infrastructure in three core components -- server, network and storage. At and in between each layer will live a virtual interface, and within those interfaces, services will be presented to the surrounding layers.

For example, let's talk about storage virtualization. The point of it is to be able to treat an underlying storage infrastructure via a common view -- masking the physical nature of that infrastructure to the higher-level layers, and so much more from the user. The point of storage virtualization is to be able to mitigate the management and data-movement issues created by direct physical requirements. We want the server layer to not need to know, or care, about where its data physically resides -- only whether its requests are being satisfied according to policy.

Data migrations are a perfect example of a service in a virtual world. Today, when IT admins need to migrate data -- and the associated users/applications between storage devices (doesn't matter if it is SAN or NAS) -- it requires meticulous planning, downtime and a lot of prayer. If something goes wrong, as it usually does, the cost can be huge. If we created a virtual layer of storage and needed to migrate 5TB from one array (which is coming off lease, for example) to another and were able to do it online, nondisruptively (i.e., without anyone knowing because there wasn't any downtime), wouldn't that be good? Of course it would.

So now that we all agree migrating between my NAS or block systems in a virtual world is a good idea, where does that service need to execute? That depends on your world. Softek Storage Solutions can migrate stuff online and nondisruptively by running at the host machines themselves. Brocade Communications Systems does it by running it as a network service, so the hosts don't even get involved. Acopia Networks can take a whole bunch of independent NAS boxes and make them look like one to the outside world -- and meanwhile, in the background, they are a living, breathing information life-cycle management control engine -- moving files around between NAS boxes based on performance or policy, all without any at the upper-level stacks having to care.