As the most prominent firm in the virtualisation market, VMware is well positioned to help companies move to virtual client desktops, and with the recent launch of its Virtual Desktop Manager, the firm can now supply all the tools needed to make such a strategy a reality.

VMware has been supporting virtual desktop PCs for several years, but with the release of Virtual Desktop Manager at VMworld in September, it now has connection broker technology that can enable large-scale deployments.

“Some customers have been putting XP VMs on ESX server for around three years ­ - they were doing [desktop virtualisation] before we were aware of it,” said Richard Garsthagen, product marketing manager for Enterprise Desktops at VMware.

These customers, however, were operating small projects in which users linked directly to a persistent virtual machine. For larger, enterprise-wide deployments, some form of broker is needed to link users and machines, according to Garsthagen. “It manages which desktop you get depending on your profile and enforces security. It’s about making the desktop efficient,” he explained.

There are several ways firms can approach virtual desktops, according to VMware. The first is to allocate each user a dedicated VM, as outlined above, but this is a lot of work, Garsthagen said. The second way is to maintain pools of virtual machines, managed by the connection broker. For maximum efficiency, these should be allocated to a user at login, then cleaned out and returned to the pool when they log out, he added.

Integration with Microsoft’s Active Directory is vital, Garsthagen explained, because this brings with it support for roaming profiles, so that staff can see their files no matter which machine they log into.

For companies sceptical about the benefits of desktop virtualisation, Garsthagen said that customers deploying the technology have found they can support six to eight virtual machines per processor core. With new quad-core chips becoming available, deployments will soon approach the density of Terminal Services environments, he claimed, where 60 to 70 user sessions are hosted per server.

Virtual Update Manager, another component of the Virtual Desktop Infrastructure, lets administrators apply patches to virtual machines, even when they are “off”. This is possible because virtual machines are accessible on the server whatever their state, unlike physical clients.

“And the beauty of virtual XP machines is that whatever customers have today to manage fat clients, those tools will still work exactly the same,” Garsthagen said.
VMware’s client also makes the connection between virtual machine and user more reliable. “If you’ve tried using RDP over a Wi-Fi connection, you’ll know that if the connection drops even for a moment, you lose your RDP session. Our technology keeps the session alive,” Garsthagen said.

Storage is the chief concern when implementing virtual desktops, according to Garsthagen, because each additional virtual machine can easily eat up several gigabytes of space. At the moment, VMware does not have its own solution to this problem, but third-party tools can address this issue.

NetApp iSCSI, for example, saves space by eliminating redundancy, so that if 100 virtual machines store the same file, such as Windows executables, these are physically stored only once.