ZDNet UK discusses “advances in virtualisation technology mean servers no longer need to be tied to a particular piece of hardware — they can be backed up or moved from one machine to another in the same way a file is copied from disk to disk.”
Now, virtual server products of considerable sophisication, such as VMWare’s ESX Server and Microsoft’s Virtual Server (purchased from Connectix), are getting close to the ideal, where a server’s physical resources can be set up to create a number of virtual servers that appear to all intents and purposes to be running on different computers. They can have their own IP addresses, see disk and memory resources as theirs alone, run their own operating systems and act autonomously. One piece of hardware can run a mix of Linux, Windows, Unix or whatever, each instance operating as a full computer in its own right.
The primary advantages of this approach are scalability, reliability and efficiency which boil down to saving money without sacrificing capability. Because a server is no longer tied to a particular piece of hardware, it can be backed up or moved from one machine to another pretty much as a file is copied from disk to disk. Adding extra processors to SMP machines, increasing memory or disk space, upgrades all the virtual servers running on those machines, and multiple servers can easily be coalesced onto one machine.
As with storage and networking, virtualisation decouples hardware from software, and software from data, so that the only thing that matters is what you want to do, not where you want to do it. We are moving at some speed to a computing world where the limitations of local resources are removed and interconnection, rather than physical compartmentalisation, defines IT’s potential.
Virtualisation could be quite useful for small businesses also. Imagine a single server running Linux and Windows (OS and applications) remotely managed with thin clients on the desktops. This can make computing affordable to everyone.