Amazon RDS - Notes - 04 - Read Replicas

AWS > Database > Amazon Relational Database Service (RDS):

When you create a Read Replica, you first specify an existing DB instance as the source. Then Amazon RDS takes a snapshot of the source instance and creates a read-only instance from the snapshot. Updates made to the source DB instance are asynchronously copied to the Read Replica.

Read Replicas are supported by the following database:
1. MariaDB DB
2. MySQL
3. Oracle
4. PostgreSQL

Noted:
1. When creating a Read Replica, you must enable automatic backups on the source DB instance by setting the backup retention period to a value other than 0.
2. You can have up 5 Read Replicas copies of any DB.
3. You can have Read Replicas of Read Replicas.
4. Each Read Replicas will have its own DNS end point.
5. You can promote a Read Replica to be a standalone DB instance.
6. You can create Read Replicas of RDS Multi-AZ source DB.
7. You can create a Read Replica in a different AWS Region.

You can use Read Replicas primarily for very read-heavy DB workloads.
Multi-AZ is for Disaster Revovery (DR) only, it is not primarily used for improving performance.


Reference:
1. AWS Documentation - Working with Read Replicas:
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html

2. Udemy - AWS Solutions Architect - Associate:
https://www.udemy.com/aws-certified-solutions-architect-associate/


最初發表 / 最後更新: 2020.01.12 / 2020.06.09