What is RDS?
RDS stands for Relational Database Service. It's AWS's managed database offering that handles all the boring stuff — patching, backups, replication, and failover — so you can focus on your application code.
Instead of installing MySQL, configuring it, setting up backups, and monitoring it yourself, you click a few buttons in RDS and get a fully functional database. It's like the difference between building a house and renting an apartment.
Supported Database Engines
RDS supports six database engines: MySQL, PostgreSQL, MariaDB, Oracle, Microsoft SQL Server, and Amazon Aurora. Aurora is AWS's own engine, compatible with MySQL and PostgreSQL but faster and more scalable.
Choosing an engine depends on your existing skills, licensing requirements, and performance needs. If you're new to databases, start with MySQL or PostgreSQL — they're free, widely used, and have excellent community support.
Multi-AZ and Read Replicas
Multi-AZ (Availability Zone) creates a standby copy of your database in a different data center. If your primary database goes down, AWS automatically fails over to the standby. It's like having a backup pilot ready to take the controls.
Read Replicas create copies of your database that handle read traffic. If your application has 10x more reads than writes (which most do), replicas distribute the load and keep things responsive.
Connecting to RDS
Once your RDS instance is running, you connect to it using the standard database tools for your engine. For MySQL, you'd use the mysql client:
mysql -h my-database.xxxxxx.us-east-1.rds.amazonaws.com -u admin -pYou'll get the endpoint (hostname) from the RDS console. Make sure your security group allows traffic on the database port (3306 for MySQL, 5432 for PostgreSQL).
RDS Pricing
RDS pricing depends on the instance size, storage, and features you enable. The free tier gives you 750 hours per month of a db.t2.micro instance for 12 months — enough for a small database.
Storage costs $0.115 per GB per month for General Purpose SSD. Backup storage beyond your allocated amount is also charged. Always monitor your usage and set up billing alerts to avoid surprises.