Within 30 days IT departments will be able to download Microsoft Hyper-V server, free hypervisor software, which lets users run several virtual machines on a single hardware server. The Microsoft product will compete directly with the market leader, VMWare ESX Server.
Both are free, but the two are very different platforms for virtualising servers in the datacentre.
VMWare is a mature product with advanced functions that support live migration. This a technology that allows enterprise users to move applications from one Virtual Machine to another without disruption, a key requirement in business continuity.
The VMWare Live migration technology, dubbedVMotion, is a paid-for add-on. It relies on a storage system called the VMware cluster file system (VMFS), which stores a virtual machine as a set of files on shared storage. The shared files can be access by two virtual machines simultaneouly, allowing applications and data to be transferred easily from one machine to another.
Microsoft's Hyper-V product is much less sophisticated. "It is aimed at small and medium-sized businesses who want to consolidate servers. Microsoft appears to be targeting users that do not need the advanced features of VMWare," says Ray Illsey, senior research analyst at Butler Group.
For organisations that want a more sophisticated product Microsoft has tied up with Citrix, to offer IT departments XenServer. The product has some of the high-end features available in VMWare, like live migration.
Ron Oglesby, service director at IT consulting firm Glasshouse Technologies, said XenServer is about half the price of VMWare, but he believes Citrix' strength will be in desktop virtualisation rather than server virtualisation.
"With the introduction of Hyper-V many businesses will simply install the Microsoft hypervisor when they install Windows 2008 Server. Those that want datacentre features will probably use VMWare, which means Citrix will have to focus on virtualisation of the desktop."
If they go the Microsoft route, users will need to check that their hardware will support Hyper-V.
Illsey said Hyper-V would only work with the latest generation of Intel and AMD server chips that support virtualisation, namely AMD Virtualization (V) and Intel Virtualization Technology (VT).
However, VMWare works on older generations of AMD and Intel server processors, which power many of today's PC servers in datacentres.
Businesses are expected to buy AMD V and Intel VT processors as datacentre servers are replaced over the next few years, which means more machines will support Hyper-V.
Users who want to use virtualisation to improve the uptime of their datacentre are likely to run VMWare with the live migration features in VMotion.
But users may deploy Microsoft Hyper-V if they are interested in server consolidation. Since it will be bundled with Windows Server 2008, users can simply install it when they install the operating system. With Microsoft entering the virtualisation market users of Citrix Xenserver will need to keep an eye on where Citrix takes the product.
Free download or bundled with Windows 2008 Server
Only runs on AMD V or Intel VT server chips
Designed for server consolidation
VMWare ESX Server
Supports all AMD and Intel serevr chips
Use for consolidation and live migration