From my experience I believe running virtual nodes has great benefits over running just a hardware node, but it depends on your long term goals.
Benefits of running a single hardware node:
- Processes have access to all system resources
- Only configuration of the hardware node is required
Benefits of running one or more virtual nodes on one hardware node:
- Can access all system resources allocated to it
- Resources can easily be adjusted to accomodate new server expansion
- Easy to backup
- Easy to restore
- Hardware node crashes, easy to move to another server within a short period of time
I'm sure there are more, but that's a start. I use CentOS on my hardware node with OpenVZ. Once Falko pointed me to vzsplit, it was trivial to configure the virtual nodes. I run Debian Squeeze on the virtual nodes, and everything runs great! Before, I tried using squeeze with bean counters on the hardware node. What a pain... It was difficult to configure. Now, I just use swappages and physpages, which makes a lot more sense.
I hope this helps generate more ideas on your decision.