Basics

• Managed DB Server as a service (DBSaaS) product.
• Supported DB Engines are PostGgres. MySQL, MariaDB, Oracle, MSSQL
• Amazon Arora is a different product than RDS though it has compatibility with some of the DB engines that run under RDS
• RDS runs within a VPC
• RDS Subnet Group defines the list of Subnets that an RDS instance can run in.
• Every RDS has its dedicated storage provided by EBS
• If MultiAZ setup is selected then Primary instance replicates to standby using synchronous replication
• ReadReplicas use asynchronous replication
• Backups happen to S3.
• In case of multi AZ setup, backups happen from the standby instance
• Costs Depend On
  • Instance Size and Type
  • Multi AZ setup
  • Storage Type (provision iops or not) & amount
  • Data transfer cost
  • Storage cost for backups and snapshots
  • Extra costs like licensing