RDS

Overview

• RDS有三種儲存
  • Provisioned IOPS Storage: 高效能，貴
  • General Purpose Storage: 一般用途
  • Magnetic Storage: 低效能，便宜，用磁帶，超慢
• RDS要從非加密變成加密：只能手動搬
  • 建立加密的RDS
  • 手動從原本的RDS搬過去
• Read-Replica在2018 Jan才support Multi-AZ deployment
• Read-Replica現在支援： MySQL, MariaDB, PostgreSQL, Oracle, Amazon Aurora，只有MS SQL Server還不支援
  • https://aws.amazon.com/rds/features/read-replicas/

Multi-AZ & Read Replication

Read-Replicas

• Can be Multi-AZ
• Use to increase performance
• Must have backups turned on
• Can be in different region
• Replication DB can be promoted to master, this will break the Read Replica
• Supported by MySQL, PostgreSQL, MariaDB, Oracle, Aurora (No SQL Server)

Multi-AZ

• Use for DR
• No maintenance required, AWS do all for you
• Can be force a failover from one AZ to another by rebooting the RDS instance

Aurora

• PostgreSQL / MySQL compatible
• Start with 10GB, max to 64GB auto-scaling
• Compute up to 32 vCPUs and 244GB memory
• 2 copies in each AZ; Minimum to 3 AZ, which is 6 copies by default
  • Design to handle loss of 2 copies without effect availability and performance
• 3 types of replications
  • Aurora Replicas: up to 15
  • MySQL Read Replicas: up to 5
  • PostgreSQL up to 1
• Auto-failover ONLY available on Aurora Replicas 
• Aurora Replica CANOT cross region
• Auto backup is enabled by default
• Aurora是一種serverless
  • 適合unpredictable workloads
  • On-daemond
  • Autoscaling for MySQL-compatible and PostgreSQL-compatible Aurora
  • Automatically start-up, shuts down on application’s needs
• Aurora Snapshots CAN be shred to other AWS account