Virtualisation is one of the hottest topics of the moment, but still represents a relatively immature sector of the IT industry, as most organisations have yet to invest heavily in the technology. According to Forrester Research, about 60 per cent of companies using virtualisation have only a year’s experience.

The main vendors are VMware, which has led the way in server virtualisation, plus Microsoft and Citrix. Each is following a different roadmap, and IT managers need to carefully evaluate their own plans before deciding which provides the best match for their strategy.

But there are signs that the strategies of all three suppliers are heading in the same direction ­ enabling greater centralisation of IT provisioning into the datacentre. We assess the credentials of the three major players.

VMware

VMware has the broadest line-up of products and management software, but its roadmap now aims beyond the server consolidation role for which it is best known.
At its VMworld conference last month, the company outlined plans for a virtual datacentre operating system (VDC-OS).

VDC-OS is essentially a plan to build out from existing virtual infrastructure tools, to turn all the servers, storage and network resources in a datacentre into one big pool to deliver the applications and service levels required by customers.

VMware likens this to creating an internal cloud infrastructure, and another initiative looks at how this might relate to cloud services operated by third parties such as BT.

If fully realised, VMware expects businesses to be able to migrate applications seamlessly out to such external providers, if this makes for a more cost-effective system. Alternatively, businesses could use extra capacity available from such suppliers to cover peak demand.

Much of this is still a “statement of intent”, according to VMware, but many of the pieces are in place, and it is largely a matter of linking it all together, it said.
VMware also unveiled another initiative ­ vClient. This is an ambitious attempt to provide workers with access to applications and data wherever they are from devices such as smartphones, not just desktop and laptop PCs.

Part of this plan involves virtual desktops ­ virtualised client machines that reside in the datacentre and are accessed remotely by users. VMware expects travelling workers will be able to download a virtual machine to a laptop or even to a USB memory stick, and take their corporate desktop on the road. Any changes can be synchronised to the server-hosted system over the internet, or when the user returns to the office.

Taken together, VMware’s plans can be seen as an attempt to re-invent the mainframe, said Butler Group senior research analyst Roy Illsley.

“It’s what I call the virtual mainframe ­ they’re trying to re-build the mainframe architecture using commodity hardware and software components,” he said.

Microsoft

Microsoft is a latecomer to virtualisation, but the software giant is catching up fast. The company released its Hyper-V hypervisor for Windows Server 2008 earlier this year and recently added a standalone version that can host guest virtual machines without an underlying version of Windows.

According to analysts, Microsoft expects to build market share by initially targeting organisations that have yet to seriously implement virtualisation, such as small-to-medium-sized enterprises.

For customers such as these, a Microsoft-based system has cost advantages ­ Hyper-V is effectively included for free as part of Windows Server 2008 (WS 2008). The standard edition of WS 2008 also includes an extra licence to cover a virtual instance of the operating system, while the datacentre edition covers an unlimited number of virtual machines.

Microsoft is leaving Citrix to compete with VMware in larger organisations for now, while assuring customers that Hyper-V will work in a Citrix-based infrastructure.
Currently, Microsoft lacks the capability to migrate live virtual machines from one server to another without any downtime, but the company has demonstrated this feature and expects to make it available in 2009.

Microsoft has also entered into a partnership with Citrix, whereby the two companies are filling out gaps in each other’s portfolio. There is some interoperability between the two companies ­ Microsoft’s System Center Virtual Machine Manager can manage virtual machines running on Citrix XenServer, for example.

Microsoft lacks a technology for operating virtual desktops in the datacentre and is relying on Citrix to provide this. But Illsley said it “doesn’t take a genius to see that Microsoft could come out with its own product if it wanted to.”

Microsoft also hinted that it will have a product aimed at cloud computing in the near future. Chief executive Steve Ballmer said this month that the company will soon unveil a platform to run applications in the internet, which he labelled “Windows Cloud”. Full details have yet to be disclosed, but it is expected that Microsoft will outline a strategy a similar to VMware’s VDC-OS.

Citrix

Citrix has approached virtualisation from the opposite end to VMware, specialising in delivery technology and access mechanisms such as Citrix Presentation Server - now called XenApp. As such, the company is well placed to provide the infrastructure needed for virtual desktops.

With the acquisition of XenSource in 2007, Citrix gained the hypervisor technology needed to consolidate virtual machines on servers, and is also looking to become a major player in cloud computing and software-as-a-service.

In September, Citrix unveiled release five of XenServer, with an emphasis on high availability and disaster recovery features. These capabilities were added to bring it closer in line to those offered by VMware, although Citrix still has some way to go before it achieves parity, according to Illsley.

“XenServer is not quite as advanced, but it has the equivalent of Vmotion [live migration of virtual machines] and brokering, making it comparable,” he said.

Citrix is already strong in remote access, and now has a complete portfolio of products for virtualising user sessions. XenDesktop, released earlier this year, is designed to give workers the same experience as using a desktop PC, even though they might be using a thin client linked to a virtual machine in the datacentre.

Equally important is XenApp, which provides application virtualisation. This allows software such as Microsoft Office to be delivered on demand rather than installed onto PCs in the conventional manner.

Citrix, like VMware, is positioning itself as a vendor that can help centralise all IT operations into an organisation’s datacentre. But the company is relying on its partnership with Microsoft to help deliver this.

A special version of XenServer will also form the core of a new platform, Citrix Cloud Centre, aimed at service operators planning to build cloud-based computing infrastructure. This makes use of other Citrix products such as Netscaler and WANscaler appliances that optimise the performance of applications over remote connections.

But Illsley said potential buyers should be aware there is no guarantee that customers will not be locked in to a particular vendor or service provider.

“The ultimate aim is to create a flexible service pool supporting independent operating systems that actually run the applications, but I don’t believe you will have interoperability between vendors completely,” he said.