VMware's VMotion caused quite a stir at the first VMworld user conference in San Diego recently. This technology enables a virtual server to be moved from one hardware host to another without interrupting the virtual server's operating system or apps.

If you haven't seen it before, VMotion is a fantastic technology and is greeted enthusiastically when people realise how it can automate server operations. VMotion is the result of combining SAN hardware, VMware's ESX server virtualisation software and its VirtualCenter management console. Though VirtualCenter does not automate the movement of virtual servers, it has been around for a year and many firms are already using it on production systems.

One speaker said his firm used VMotion to upgrade a network switch during the middle of the day without interrupting users. Without VMotion the upgrade would have required out-of-hours overtime.

Early adopters are confident VMotion is reliable, and people at the show were told the next version, due next year, will include automation capabilities. It will harness various metrics, such as processor utilisation, which, combined with management policies, will enable busy virtual servers to be moved to more powerful hardware. It will also monitor virtual servers and their hosts, and if a server stops, VirtualCenter will either restart it or move it to a new host and then restart it.

Currently this stuff only works when all the hosts are connected to the same SAN and share a gigabit LAN. However, there would be jam today for anyone who can make this work with multiple datacentres.

Clearly, there's a connection between this type of capability and the ideas behind the concept of service-oriented architecture (SOA) that is being promoted by most enterprise software vendors this year.

The idea behind SOAs is to think holistically and provision automatically. For example, an e-commerce site is a service, probably made up of several apps. I'd hope to find a web server or two to present the site to the users, plus a back-end database to process data about orders and customers. And there would be some middleware to join all this together.

Rather than managing the individual apps, the SOA concept says use an automated management console. If response times from the web site are too slow, add more web server capacity. If the transaction queue to the back-end database gets too long, add some more database servers or re-provision the storage.

Of course, the ability to change down a gear is equally important, and all this would only be interesting if the whole system were automated. Most current technologies do not allow apps servers to be adjusted in this way, but it would be fairly simple to use next year's VirtualCenter to start up new instances of a server. It's a radical shift, but that's where the money is.