Sun is set today to upgrade its Virtual Desktop Infrastructure (VDI), expanding the widgetry’s operating system repertoire to Windows 2000, OpenSolaris and Ubuntu and its VMware support to multiple copies of vCenter and ever larger desktop deployments.

More importantly, perhaps, the new VDI 3 addresses what Sun says is a key barrier to virtual desktop adoption: the vast amounts of storage it usually demands.

Sun says if users install its Open Storage operating system, a subset of Solaris, they won’t consume the wasted disk space usually eaten up by heavy VM duplication and Solaris’ nifty ZFS widgetry will provide snapshot functionality so only changes are saved.

It claims “groundbreaking storage economics.”

Like its predecessor, VDI 3 supports XP and Vista, but it now supports more than just Windows operating systems by leveraging Sun’s own VirtualBox widgetry. Users can also use a mix of VirtualBox and VMware, which offer different features.

Sun’s also promising easier, less time-consuming installation complements of a single installer for the core components that reportedly reduces the aggravation to an hour, two to four times less it used to be.

The widgetry used to require software on the client. Now there’s built-in support for the ubiquitous Remote Desktop Protocol (RDP) so RDP-enabled devices – which is just about everything on the desktop – can connect directly to the VDI 3 server.

And there’s Active Directory support, a sine qua non in desktop-land, so virtual desktops can be assigned to user.

With the expanded VMware support, Sun said a user should be able to get 160 virtual machines to an x86 server the size of one of its fairly hefty x4600s.

VDI 3 is supposed to demand less energy and cooling. Data never leaves the corporate network. Used with Sun Ray thin client, the desktop is practically immune to client-side viruses.

VDI starts at $40 a user a year. There’s free trial software at www.sun.com/software/vdi/get.jsp.