SMP-Enabled Sun xVM VirtualBox 3.0 Turns Up the Heat on VMware

Version 3.0 of Sun's xVM VirtualBox desktop virtualization tool adds support for multiple guest processors--a major feature addition that, when considered alongside the product's low cost (free) and broad host platform support, is certain to give VMware Workstation a run for its money.

Sun Microsystems' xVM VirtualBox, a no-cost virtualization tool that enables virtual machines to run on a variety of standard operating systems, continues to improve its position as a potential challenger to workstation products from VMware and Parallels.

Sun released Version 3.0 of xVM VirtualBox on June 30 and added symmetric multiprocessing (SMP) as the major new feature.

I tested VirtualBox 3.0 on a Sun Fire x4170 server running Windows Server 2008 64-bit and equipped with 12GB of RAM and two quad-core Intel Xeon x5570 "Nehalem" processors. On this machine, I was able to create guests with up to 16 virtual CPUs by taking advantage of hardware-enabled hyperthreading. I also tested it on a Lenovo T400s laptop running Windows Vista and equipped with an Intel Centrino Core 2 Duo CPU and 2GB of RAM, and on a Mac mini running OS X to run Windows XP.

Check out images of VirtualBox 3.0 here.

In all cases, xVM VirtualBox installed and ran without problems. When I tried to assign virtual processors to a guest on the Lenovo notebook I was warned to enable I/O APICs (Advanced Programmable Interrupt Controllers) to avoid IRQ sharing.

xVM VirtualBox did not prevent me from assigning more virtual processors than were available on the physical host. In the case of the Sun Fire x4170 I was able to assign 32 virtual cores to a guest even though that was twice the number of available cores. And even that was "cheating" by using hyperthreading to double my eight physical cores. The user documentation clearly indicated that virtual cores should not exceed actual available physical cores.

Aside from SMP, xVM VirtualBox consists mostly of tweaks to existing features, including experimental support for hardware 3-D acceleration by supporting DirectX 8/9 and OpenGL programming interfaces. While "no cost" is the most compelling reason to look at xVM VirtualBox, the addition of SMP support along with the relatively quick tempo of product development-Version 2.2.4 was released at the end of May-recommends the product as a serious platform of IT pros.

Beyond the feature additions and improvements, there is a long list of bug fixes that include patches for various guest performance problems and for issues regarding the way VirtualBox handles the importing and exporting of OVF (Open Virtualization Format) virtual appliances. For the full list of VirtualBox 3.0 changes, see

In addition to Windows and OS X, VirtualBox supports Linux, Solaris and OpenSolaris as host operating systems. VirtualBox is available for free download at

Technical Director Cameron Sturdevant can be reached at