Thorsten: <i>By the time one follows best practices one should end up with a system that is as resilient to coordinated EBS failures as to other coordinated failures in an availability zone, so the use of EBS doesn’t seem to introduce significant new factors.</i> You'd think so? Netflix is basically the only one who manages to stay up when there's an AWS failure, and they have now come out saying they don't use EBS for critical storage. I myself have also started to move away from EBS. So I think this is a step backward. Independent failure is much better, because you can handle that with replication. EBS failure is crippling for an entire AZ and often cross AZ. (ELB goes down, EIP doesn't work). Secondly, cross AZ traffic is highly expensive. Unless Amazon drops cross AZ cost with a factor of 10, cross AZ sites are not within reach of many. So I would conclude this will increase the number of widely noticed failures as there are less options, and newer folk believe the EBS hype (more reliable than disk blablablah), without noting that EBS availability is a significant problem.