EBS is another great service from Amazon. The company continues to innovate. Werner had talked about this service in the past but now it’s available. Well done Amazon! The Amazon Web Services Blog has more.
I found the pricing model interesting. While traffic from EC2 to S3 is free (unless you cross the Atlantic within Amazon‘s infrastructure), your IOs against EBS will cost you (in millions of requests). I guess algorithms/applications will have to calculate the convenience and features of EBS against just using S3 at no cost (in terms of IO). Also, there is an interesting balance that developers will have to strike between maintaining things in memory in EC2 (paying for time) for their distributing computing algorithms (communication between EC2 instances is free) and doing taking advantage of the persistent, fault tolerance-related features of EBS (paying for IO requests).
Amazon‘s execution on Cloud Computing is brilliant!