Am looking at a retail web app on AWS because of easy scaling and replication, etc., along with cheap startup. We hope for 10,000 simultaneous clients with lightweight use per client and only some 1GB of product and 10GB of customer data.

(In AWS, a reboot can spin vCPUs and DB speed up or down, and replicated servers can be invoked with load. For instance, AIRBNB and Pinterest runs thousands of AWS "instances" , varying with load. An instance has 1-32 vCPUs and 1-60 GiB RAM.)

Once I have a working app I will load test, but is does anyone have experience with AWS?

CloudNexa, who administers AWS systems, recommends SQL Server over MySQL because it "talks better" to IIS. ??

Anybody know offhand how MySQL replication costs compare to SQL Server?