My interview process in 2007 was as follows:

1. A phone interview with a recruiter to ensure I was a fit for the job.
2. The hiring manager called to discuss my work experience and ask a few position-related questions.
3. An on-site interview.

The questions weren't hard. They covered linked lists, general debugging approaches, and everything was written on the whiteboard. Then, the last person I met with, a nice guy, informed me that I was being considered for three positions and that the recruiter had made a mistake, scheduling the wrong people. I was supposed to interview with six people for a HARDWARE position, but the recruiter had scheduled me with six SOFTWARE engineers who didn't even work with the teams I was supposed to interview for. There was no follow-up from the recruiter either. Worst recruiter ever.

Google has 300 servers around the world.

Servers are failing about 1 every month.

How would you go about debugging the failure?

That's great, good answer.

The failure is actually random. Nothing you've tried is able to duplicate the failure exactly the same.

How do you approach this?

Another good answer.

Now, what do you think is actually the cause of these failures?