I. Introduction

1. RDBMS in AWS is called RDS (Relational Database Service)
2. Used in OLTP scenarios.
3. DB instance is the building block.
4. Only pay for the instances that are active.
5. RDS includes SQL Server, Oracle, MySQL, MariaDB, PgSQL and Amazon Aurora.
6. Key features of RDS include:
   • Automatic provisioning, OS patching
   • Continuous backups and restore to specific timestamp
   • Monitoring dashboards
   • Multi-AZ for disaster recovery
   • Read-replicas for performance
   • Storage backed by EBS (GP2 or IO1)
7. RDS runs on virtual machines but you can't log into them.
   • Patching is Amazon's responsibility
   • It is NOT serverless (except Aurora)
8. AWS also provides data warehousing with tools like Cognos, JasperSoft, SQL Server Reporting Services, Oracle, Hyperion, SAP NetWeaver.
   • These are used to pull in very large and complex data sets. Usually used by management to do queries on data
   • Redshift is AWS' data warehousing solution
9. It's important to identify what kind of database you need based on use case — OLAP vs OLTP.
10. ElastiCache is a web service that makes it easy to deploy, operate and scale in-memory cache in the cloud. The service improves the performance of web apps. ElastiCache supports two open-source in-memory caching engines:
    • redis
    • memcacheD
11. RDS supports encryption at rest and is done using KMS. Once your RDS instance is encrypted, the data stored at rest in the underlying storage is encrypted along with its automated backups, read-replicas etc
12. For MS SQL, the max size RDS volume is 16 TB
13. Regular metrics available by default including CPU utilization, database connections and freeable memory

II. RDS for SA

1. Operations
   1. Small downtime when failover/maintenance happens
   2. Scaling in read replicas/EC2 instance/restore EBS implies manual interventions
2. Security
   1. AWS responsible for OS security
   2. We are responsible for setting up KMS, security groups, IAM policies and user auth
3. Reliability: Multi AZ feature, failover in case of failures
4. Performance: Depends on EC2 instance type, EBS volume type, ability to add read replicas. Does not auto scale.