When I was working on Live Mesh at Microsoft, I had the good fortune to meet James Hamilton. James is full of good ideas, many of which are captured in his paper “On Designing and Deploying Internet-Scale Services.” There is a lot of wisdom in those pages (Greg Linden had some thoughts on it), but I’d like to focus in on this snippet in particular:
Design the system to never need human interaction, but understand that rare events will occur where combined failures or unanticipated failures require human interaction.
When you are running a distributed service in a datacenter, you encounter a lot of interesting problems. At Audiogalaxy, I ran into all the standard application level bugs, crashes, and race conditions. Once we had a certain number of machines, we even had to deal with flaky memory, disks, and networking cards. But all of that was pretty typical compared to the weirdest bug I ever had to deal with – the one that was caused by Quake III Arena.