The Zen of Hosting: Part 9 - Hyper-V
As I approach the end of this series, I want to highlight some of the technology that the hosting machine is built on and some of the experiences I learned with that. These last few posts are much shorter than the earlier ones but hopefully provide some quick bite-sized info.
So if you have looked at standard HMC, then add all the technology we have added to it, you would assume there is a building full of servers. The reality is the server room has got lots of space and isn’t that big. How did we achieve this? Slow applications because we are running everything on fewer servers? Not at all.
We bought some seriously powerful HP machines, loaded them with a ton of RAM, and installed Windows 2008; but how does that help with running lots of systems? And doesn’t HMC break if it runs on Win2k8 (see way back to part 2)? Well, Win2k8 has the best virtualization technology Microsoft has ever developed, named Hyper-V. This is seriously cool stuff—in that it actually runs before Windows starts and virtualizes Windows completely (rather than running virtual machines on an OS, they run next to it). The performance compared to Virtual Server is not even worth talking about; it basically pushes Virtual Server into the stone age.
It is very fast and seems to handle the randomness of the servers’ usage (those little spikes when you run multiple machines on one piece of hardware) so well. But not everything is virtualized: there is a monster of an active-active SQL Server cluster (since so much needs SQL), and we have a number of oddities, such as the box which does media streaming—due to the fact that some specialized hardware can’t be used in a virtual machine. A worry for when we started with Hyper-V was its beta/RC status... Well, with thousands of hours of uptime logged so far by servers on it, it has been ROCK-solid.