How does Amazon RDS calculate I/O rate?

I browsed the Amazon RDS pricing site today and now do want to know how they actually calcula开发者_高级运维te the I/O rate? What does "$0.10 per 1 million requests" really mean?

Can anyone give some simple examples how many I/Os a simple query from EC2 to a MySQL on RDS produces?

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In general it is a price for EBS storage service. Amazon claims something like this for EBS (section Projecting Costs):

As an example, a medium sized website database might be 100 GB in size and expect to average 100 I/Os per second over the course of a month. This would translate to $10 per month in storage costs (100 GB x $0.10/month), and approximately $26 per month in request costs (~2.6 million seconds/month x 100 I/O per second * $0.10 per million I/O).

If you have a running application on Linux, here is an article how to measure cost for EBS: