This section provides information about my XEN cluster with share storage that I currently use at home. It consists of two machines with identical hardware and software. A two node cluster utilizing XEN, DRBD and Heartbeat. I will here describe in detail how I did it.
A friend of mine always asks for the reason for doing things. Why? Why are you doing this? Especially this project can seem like a stupid thing to do in your home. Why would I need High Availability (HA) XEN cluster with shared storage?
I actually had several reasons. The main one being the lack of safe storage, especially for pictures and documents. Until now I had everything stored on our desktop computer, so in case of a crash I could lose everything. I had also a mini-itx server running Asterisk, being a media server and VPN server. This server was without redundancy and was also getting slow as I tend to install more and more things. So I thought that the best idea was to build a cluster with shared storage to get the redundancy, and then run virtual servers to be able to separate Asterisk from my file server.
I decided to use XEN for my virtual environment, being open source and seemed to have the best features. With XEN you normally have virtual machines (VM) running in, what is called, para-virtualized mode, as compared to fully-virtualized. But with newer chipsets and CPUs from AMD and Intel built with extensions for virtualization, XEN supports both modes. Intel-VT or AMD-V are the names of this technology. I wanted to be able to run both modes as fully-virtualized makes it possible to install a VM directly from an iso image, CD or DVD. I compared Intel-VT and AMD-V and made the decision to go with AMD-V. It seemed as Intel did not properly support or had the correct implementation of all features, causing certain VM installations to fail. And another factor was the price. AMD was way cheaper than Intel.