RDS (Relational database service)

RDS

• It’s a managed SQL database service. (related: SQL vs NoSQL), so it’s less complicated than manually configuring an EC2, for example
• It handles daily or automated backups, patching, and you can enable multi-AZ for high availability
• You can create multiple dbs & multiple db engines
• They are db software running on top of EC2 instances under the hood
  • An RDS instance is like an EC2 instance that is specifically designed to run a database
• A regional service

Configuration

• diagram
• choose an engine
  • You create a new db by choosing an engine (ex. MySQL, PostgreSQL)
    • One of the options is Aurora
  • choose version of the engine
  • settings (ex. whether you want to automatically update to newer versions)
• choose hardware & network configuration
  • Instance class (hardware profile), kind of like choosing a hardware profile for an EC2 instance
  • Choose a VPC, subnet, security group to attach to the db
• configure db server
  • login credentials, port
  • Replication settings
  • monitoring settings to get insights

Aurora

• diagram
• It is a SQL engine created by Amazon for AWS, with many built in optimizations
  • Compatible with MySQL and PostgreSQL
  • Has lots of great features built in
  • Not an engine you can install on your local PC
  • Can be a great choice for a relational database, an alternative to MySQL and PostgreSQL
• NOT part of the free tier (can easily get quite expensive)
• Aurora Standard VS Aurora Serverless
  • Aurora Standard
    • the default, more often
  • Aurora Serverless
    • removes the need to manage database servers manually
    • automatically scales and pauses when not in use, making it cost-effective for variable workloads.
    • near-zero cost when idle
    • less features than the non-serverless version
  • Serverless feature is only available for Aurora

Pricing based on engines

• RDS with Standard Engines (Fixed Payment)
  • Engines: MySQL, PostgreSQL, MariaDB, SQL Server, Oracle
  • Pricing: Charged per hour (whether used or not)
  • Think of it like renting a dedicated database server
• RDS with Aurora (Two Pricing Models)
  • Aurora Standard: Charged per hour (like regular RDS)
  • Aurora Serverless: Pay-as-you-go, billed per second based on usage

Replication settings

• diagram
• RDS supports Multi-AZ deployments for high availability.
  • AWS can replicate your database to another AZ for redundancy.
  • If the primary database fails, AWS automatically switches to the standby in another AZ.
• Useful to make backup instances
• Kind of like S3’s replication feature