I am currently using VirtualBox on a Windows XP (32bit) host, with a triple core AMD Phenom 2.29GHz and 3½GB of RAM.
I run Selenium 'hub' on one of the virtual machines, and various browser configurations with Selenium RC running on the others. I am seeing a performance issue that will prevent me from scaling this solution, so would like to put together a proposal for purchasing new hardware.
Essentially the virtual machines will only be launching and driving web browsers. I suspect my current bottleneck is writing to the hard drive. Rather than trial and error hardware replacements/additions I would prefer to just get in some suitable hardware to handle my requirements.
Has anyone solved this themselves, or perhaps a similar problem? What is the recommended hardware for a virtualization server where the VMs are running concurrently and all potentially writing to disk?