Adventures in virtualisation

And it continues…… Xen would be nice, but XenExpress’ hardware support isn’t perfect. I realise that it’s a bit much to expect it to support my wi-fi hardware, but it would be nice. Xen is a paravirtulisation solution. It usually uses a custom kernel for each “guest” machine to translate it’s direct hardware interaction into interaction with the virtualisation “engine”. The upside of this solution is that the virtualised servers run almost as fast as if they were running on bare hardware. The down side is that you cannot run closed source operating systems (unless the OS developer supplies a Xen compatible kernel, which they don’t). The new Intel and AMD CPUs supporting VT and AMD-V features remove this restriction, but my intention is to run this on a 3.4GHz Intel Northwood P4 CPU, which doesn’t support VT. I’ll come back to Xen when the driver support is better, and I have a VT or AMD-V CPU to play with.

My next option was to try VMware’s new free VMware Server application. It installs as just another application on a base OS, so if the OS supports the wi-fi card, VMware will. It’s a fully virtualised solution, so stock OS kernels interact with the VMware server application instead of the hardware. It takes 10 minutes to install and it works just like having VMware Workstation installed on a local PC, only with the additional benefit of the VMs staying running when you disconnect from the server.

The server is now up and running (it’s a Dell PowerEdge 400sc, with a 3.4GHz P4 CPU and 2GB RAM) and is running 2-4 VMs. A Debian Etch email server (Postfix/Courier-IMAP) and a Debian Etch web server (Apache/PHP/MySQL) are running constantly, and I run a Windows 2003 and/or CentOS VM when I need to.