Overview
An RDS Parameter Group is a container for engine parameter values that can be applied to one or more database instances. Once you create an RDS Parameter Group, you will be able to specify values for each parameter. Create multiple parameter groups in order to define different sets of parameter values.
A default RDS Parameter Group (e.g. default.mysql5.1) will automatically be created for you if you launch an RDS Instance for the first time (and you have not already created a parameter group).