Microsoft postpones Viridian Windows Server virtualisation features

Stephen Withers
Friday, 11 May 2007 06:37

Business IT - Technology

Significant features previously planned for the first version of Microsoft Windows Server virtualisation (code named 'Viridian') have been postponed to a later release.

Mike Neil, general manager of virtualisation strategy, said yesterday "we've made good progress with Windows Server virtualisation" and a beta release will be available alongside Windows Server 'Longhorn' in the second half of this year.

But at the same time, he revealed three features that will be missing from the first version.

Live migration allows the transfer of a virtual machine from one physical server to another without first stopping it. For example, a mail server running on a physical server that's due for an upgrade could be temporarily moved to another box while the work is performed, and then back again. With live migration, there would be no apparent break in mail availability. But that won't be possible with the first release of Viridian.

Hot add refers to the ability to physically add or remove resources such as storage devices, network interfaces, memory and CPUs. While Windows Server 2003 supports memory hot-add, for example, intending Windows Server virtualisation users will have to wait until an unspecified future version for that ability.

Competing virtualisation systems already have these features. Xen currently supports hot add. VMware has offered live migration for several years, and Xen has it in a limited form that will soon be extended to Windows.

The third negative change is that the first release will have a limit of 16 cores or logical processors, so top end hardware for this version would be a quad four-core system. That's not such a big deal in the short term, as few x86-based servers have more than 16 cores.

"So we had some really tough decisions to make. We adjusted the feature set of Windows Server virtualisation so that we can deliver a compelling solution for core virtualization scenarios while holding true to desired timelines," said Neil.

"Windows Server virtualisation is a core OS technology for the future, and we chose to focus on virtualisation scenarios that meet the demands of the broad market – enterprise, large organizations, and mid-market customers."

Last month, Neil announced the beta would be delayed from the first half to the second half of the year. At the time, he pointed to hot-add and 64 processor support as reasons for the delay.