XenSource is set to move out of the shadows of rival VMware with the launch of XenSource Enterprise v4, its latest enterprise-class virtualisation product.

The company hopes v4 -- launched earlier this week -- is a "significant milestone in the company's transition from a next-generation technology leader to a provider of comprehensive enterprise-class virtualisation solutions", according to a statement.

With the Enterprise v4 product, XenSource is targeting the same enterprise customers that VMware is now targeting as both companies look to take virtualisation from the realm of departmental systems into large cross-company deployments.

A key component from XenSource will be the 64-bit hypervisor which, on paper, is one of the most powerful available. It has the ability to address up to 128GB of physical memory and a much larger number of CPUs than has been available so far. Each virtual machine can have 32GB of memory and support up to eight CPUs.

Another feature designed to appeal to enterprise customers is resource pooling. Multiple physical systems may be combined into a pool of virtual resources, allowing virtual machines to be moved from one physical resource to another, enabling greater flexibility of systems.

That flexibility is one of the key benefits that enterprises are now seeking from virtualisation. Enterprises typically want the ability to shift resources around as quickly and easily as possible, as requirements change.

Using version 4, XenSource says it is now possible for systems managers to "drag and drop" virtual machines into a pool of resources, with the pool assigning the resources according to priorities set by IT managers.

Another key new feature in XenSource is support for a range of direct attached and shared storage architectures for virtual machines, including virtual disk images using NAS, iSCSI and SAN. Key to this is a link-up with Symantec's Veritas Storage Foundation product suite, which will now be included as an integrated component within version 4.

XenSource's co-founder and chief technology officer, Simon Crosby, believes that the link-up with Symantec is a core feature for his company. "Through Symantec we have access to all their test gear," he told ZDNet Australia's sister site ZDNet.co.uk.

Now is the right moment for XenSource to make its mark in the enterprise market, according to Crosby. He believes the company has been able to enjoy living in the shadow of VMware, as it has striven to "do things better", he said. "We are definitely the better product," said Crosby.

As he points out, the company has no operating-system agenda. "We work with Microsoft and Sun, for example," Crosby said.

But XenSource is still a small company, claiming 500 paying customers and 5,000 production users as of the end of the last quarter.

"The market is really looking for a credible number two. We are that company," said Crosby.

XenSource Enterprise v4 will be released on 20 August, and it includes as standard features: XenMotion, XenCenter, a 64-bit hypervisor and XenAPI.

Pricing for XenSource Enterprise starts at US$1,599 for an annual subscription licence per dual socket server, and US$2,499 for a perpetual licence per dual socket server.

XenSource's midrange product, XenServer v4, includes as standard features: XenCenter, a 64-bit hypervisor and XenAPI. XenServer v4 does not include XenMotion, but the previous limits on guest virtual machines (VMs) and memory will be removed, the company said.

XenServer will also now have the ability to manage both Linux and Windows guest VMs. Pricing for XenServer starts at US$495 for an annual subscription licence per dual socket server, and US$750 for a perpetual licence per dual socket server.

XenExpress continues as a freely available download from the XenSource site.

Colin Barker reported for ZDNet UK from London.