Subir Parulekar and Rahul Pilani describe how they moved their billing data out of a data center and into AWS:
Now the only (and most important) thing remaining in the Data Center was the Oracle database. The dataset that remained in Oracle was highly relational and we did not feel it to be a good idea to model it to a NoSQL-esque paradigm. It was not possible to structure this data as a single column family as we had done with the customer-facing subscription data. So we evaluated Oracle and Aurora RDS as possible options. Licensing costs for Oracle as a Cloud database and Aurora still being in Beta didn’t help make the case for either of them.
While the Billing team was busy in the first two acts, our Cloud Database Engineering team was working on creating the infrastructure to migrate billing data to MySQL instances on EC2. By the time we started Act III, the database infrastructure pieces were ready, thanks to their help. We had to convert our batch application code base to be MySQL-compliant since some of the applications used plain jdbc without any ORM. We also got rid of a lot of the legacy pl-sql code and rewrote that logic in the application, stripping off dead code when possible.
Our database architecture now consists of a MySQL master database deployed on EC2 instances in one of the AWS regions. We have a Disaster Recovery DB that gets replicated from the master and will be promoted to master if the master goes down. And we have slaves in the other AWS regions for read only access to applications.
Read the whole thing. Their architectural requirements probably won’t be yours (unless you’re working at a company at the scale of Netflix), but it’s quite interesting seeing how they solve their problems.