I'm using aws to run php app and it works good.
But I have a question: Does Any one knows if accessing to RDS from ec2 in the same region can trigger bandwith charge ?
Thanks.
If both the RDS and EC2 servers are in the same availability zone then there is no data transfer charge. If they are in different availability zones then there is the standard data transfer charge on the EC2 instance, but no transfer charge on the RDS instance. In addition, there is no charge for RDS data replication between availability zones.
This information used to be on this page, but now I can't find it. You can see some of this information in the RDS FAQ page. There is also a discussion thread on the official RDS forum here.