I just got two HP ML350 servers (very nice: 8 gb RAM, 600 gb 15k disk, 2x 3.6 GHz Xeon -- yes, we over-ordered) and I spent a few hours installing Xen-enabled Debian on them.

Xen is a very nice virtualization system that works with Linux. It lets you do things like run multiple virtual machines on top of Linux, save/restore/checkpoint them, and migrate (live!) virtual machines across physical machines. I'm planning to use it to run some Web servers & also to provide isolated development environments for people who absolutely require root privs. (Read this Xen documentation for some pretty clear overview docs on the commands available.)

After struggling for many hours, I got the Xen install down to 30 minutes. The guide I found most useful was this article on Debian Sid gets Xen 3.0 by Steve Kemp (an advogatoan!), but the process is even simpler now: briefly,

0. Install Debian minimal.
1. Switch to 'unstable' in your apt sources.
2. apt-get dist-upgrade
3. apt-get install xen-linux-system-2.6.18-1-xen-686
4. Do the rest of the apt-gets mentioned in the article above.
5. apt-get install xen-tools
6. (If you want network bridging) Edit /etc/xen/xend-config.sxp and put (network-script network-bridge) in instead of network-dummy.
7. Reboot.

...and voila, you should be able to create Xen virtual machines with xen-create-image!

Now hopefully I can set up some cheeseshop-based kwalitee testing in my virtual machines...

--titus