I recently read an article AWS: The good, the bad and ugly, which mentioned that they've moved off of all EBS backed AWS features. What features are explicity (EBS backed EC2 instances) or implicitly (AWS web console) backed by EBS?
EBS is used instead of what Amazon calls ephemeral or instance store because random access IO is apparently better. Sequential IO can be faster on an instance store volume.
Not EBS Backed
I am almost positive that SES, SNS, SQS and SWF do not use EBS.
I do not think ElastiCache, CloudFormation, CloudWatch, IAM, or CloudSearch use EBS.
I commented on that blog article which was subsequently deleted by the author. You may wish to consider that level of professionalism as you read his post. What I wrote:
AWS has never had a region-wide failure. If the blog author had taken the time to read the two incident reports that he linked to, he would have learned that. A properly designed AWS deployment always uses multiple availability zones. The worst impact that I've experienced through both events was slightly degraded performance or intermittent API access; neither of which were a slow stopper.
What I didn't add to my original comment:
99% of the flak thrown at AWS is by people who don't understand how to properly use it. They treat it as just another VPS or just another co-lo server. You have to build your application with a cloud-based deployment in mind. It must tolerate random node failures, use stateless application servers, and seamlessly work across multiple instances and subnets behind one or more load balancers. You should be using loosely-coupled components and communicating between tiers using message queues.
In short, this blog post was just another long-winded rant by someone who doesn't understand how to use the tools they've chosen.