Introduction

Amazon RDS is a relational database service available on Amazon Web Services. It is essentially a managed database server with a volume for the data. Both cost money. Having a large dataset is not the only reason have big volume: the volume size determines the number of I/O operations (IOPS) the volume can do. If you have high load on your RDS instance you may very well run out of IOPS which can result in a disaster. Scaling up the volume size is easy to avoid such disasters, but it is much more difficult to reduce RDS storage size. This is because downsizing RDS storage size is not officially supported by AWS. If the load on your RDS instance goes down (e.g. due to refactoring), you may end up having a database with an oversized volume that costs lots of money for no reason.