Amazon Senior Software Developer interview questions

I first passed two phone interviews, with standard algorithm and design questions, similar to ones posted on GlassDoor. I was flown to Seattle for interviews. The hotel was nice, but breakfast was not included. I interviewed with 9 people, some 1:1, but most 2:1, and one 3:1. Most interview questions can be found on GlassDoor, or are very similar. The final interview was with the "bar raiser", which I basically failed. I also had a hard time with an algorithm efficiency question since the interviewer misunderstood my code. In general, the people were smart and nice. Questions were pretty much the same as posted on this site. The bar raiser asked questions requiring familiarity with implementation of Reliability and Durability within a distributed messaging system architecture. I was surprised to learn that Amazon developers are periodically on call, and even more surprised to learn they can expect to be called when they are! I would say the interview questions were more difficult than average, but it is hard to maintain high energy and mental agility through so many interviews, so I rate the process Very Difficult.