databases-rds-backup-multiAZ-readreplicas.txt

Automated Backups
- Allow you to recover database to any point in time within retention period (1-35 days)
- Take full, daily snapshot
- Store transaction logs
- Enabled by default
- Stored in S3, free equal to size of database
- Deleted when RDS instance is deleted

Snapshots
- Database snapshots are done manually (stored even after RDS instance is deleted)


Restoring Backups
- When using either restore option, restored version of database will be a new RDS instance with new DNS endpoint


Encryption
- Done using AWS Key Management Service (KMS)
- Encrypting existing RDS is not currently supported


Multi-AZ RDS
- Used for Disaster Recover (DR) only
- Availability
  - SQL Server
  - Oracle
  - MySQL Server
  - PostgreSQL
  - MariaDB


Read Replicas
- Used for scaling, not DR
- Must have automatic backups turned on to deploy a Read Replicas
- You hcan have up to 5 Read Replicas of any database
- Allow you to have a read-only copy of your database
- Achieved using asynchronous replication
- Used for performance improvements, read-heavy database workloads
- Each read replica will have its own DNS end point
- You can have read replicas that have Multi-AZ
- You can create read replicas of Multi-AZ source databases
- Read Replicas can be promoted to be their own databases (breaks replication)
- You can have a read replica in another Region