For the past year, I’ve been running Zorched.NET on a Virtual Private Server (VPS). Virtualization is not a new technology, IBM was doing it WAY back in the day. But recently it has become a lot more common as hardware has gotten so much more powerful. Why let hardware sit idle when you can run multiple Operating Systems at the same time? Virtualization takes advantage of the fact that you can get fewer, faster computers in a small package and save a lot of money over trying to get more, but cheaper boxes in a hosted rack. It also gives you the advantage that you can use the whole machine if the other Virtual systems are idle.

My host was running User Mode Linux (UML). User Mode Linux basically runs an instance of Linux in userspace on top of the base Linux system. It runs a whole instance of the operating system is running just like a regular application.

Unlike UML, Xen does not run ontop of another operating system. Xen is a thin piece of code that runs directly on the hardware and then “real” operating systems run on top of that. This method allows them to achieve really good performance.

All of this discussion is background for the fact that over the last few months I’ve been pretty dissatisfied with my VPS solution. It only had 100M of RAM, with a guaranteed 100Mhz of CPU - pretty good specs for a computer from 1995 but not up to snuff for 2006. I began looking around and found Slicehost. They offer Xen virtualized Linux instances for sale. They have a 256MB version for the same cost that I was paying for my 100MB one before. Likewise they have about (at most) half the number of virtual instances on a given machine. This means there is a lot less contention for resources. One of the biggest things that you lose is disk resources, imagine 40 different OSes all sharing the same disks, all spinning to get their own data and you understand pretty quickly. Slicehost uses RAID 1 disk and so far I have yet to see my iowait time get above 4% where I saw it hit 90% on my previous host.

So far I’ve only been using the new host for less than 24 hours so I can’t report too much. But, so far so good from a performance point of view. Hopefully you all will notice some performance improvements. Check out Slicehost, you can sign up month-by-month with no contract, so the risk is pretty low.