Unix Virtualization: When done with x86 virtualization, mainframe virtualization is what you'll turn to!

So maybe IBM is just waiting for that 360 degrees turnaround of the market and we'll all go back to the time-sharing age.

We are absolutely seeing interest in mainframes from clients who want to use more virtualisation," says Roy Illsley, a senior research analyst with Butler Group. "It's not an approach for everyone but, done well, it can reduce power consumption and footprint, improve reliability and provide a lot of value to the business."

Although virtualisation is most often discussed in terms of Wintel and Unix servers, the idea of consolidating many workloads onto a single machine and creating 'virtual partitions' was invented on the mainframe in 1967, says Carl Greiner, an analyst with Ovum. "This isn't a new idea by any stretch of the imagination, and virtualisation has always been done on mainframes."

The key advantage of using a mainframe for virtualisation is that it improves performance, says James Governor, a principal analyst with RedMonk. "Virtualisation technology on the mainframe is very mature, and offers availability, stability and security. For some applications and some customers, that's tremendously important."

Increasingly, companies are also coming around to the idea of mainframes offering better utilisation and efficiency, adds Illsley. "If you're looking to build a datacentre in London and you have the choice of consolidating onto 20 or 30 Wintel servers with the associated power and cooling bills — or a single mainframe that will use less power and reduce your footprint — well, it's quite compelling, for some companies," he says.

Today's mainframes can run thousands of virtual machines with very high utilisation rates, excellent security, downtime that's measured in minutes, and relatively low power consumption when measured as price per MIPS (millions of instructions per second).

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