In terms of hardware issues, Ive had a single EC2 instance running application servers and MySQL (YUP - ran a decently traffic intensive site like this). All so

In terms of hardware issues, Ive had a single EC2 instance running application servers and MySQL (YUP - ran a decently traffic intensive site like this). All software was run on a virtual instance. I configured all the necessary things to run on startup of the machine and the worst thing AMZN ever did was occasionally reboot the host machine my instance was running on. I was never down and there were "planned restarts" that I'd get the odd email about. In the event some real failure happened, I had a clone of the AMI and could easily dump it onto new hardware - after I knew about it of course. All that said - that situation wasn't my Job - and if Im being paid to have uptime, Id better cover my ass and have a hot failover on standby. Since Im speaking AWS here - of course I used EBS for the virtual filesystem such that a machine crash didn't lose my SSD based filesystem. As I'm sure many here know, you can run a database on an EBS backed filesystem (and I have to assume even mount a swap file there too). I thought it was crack-smoking a when someone suggested that could easily be done. "But if its that simple - why is everyone running all these N tier setups and living with all this unnecessary complexity?!?!"