RDS
Default: Single DB provision on EC2
Reliability Architecture
- you need to enable the Multi-AZ feature on your RDS instance and replicate it synchronously to a standby replica in another Availability Zone. (up to only 1 sync replica)
- put up 1 Read-only async replica in another Availability Zone
- Storage Auto Scaling, up to 64 TB (SQL server 16TB)
- Cluster Endpoints
- RDS does not provide a load balancer for read replicas.
- There is a cluster endpoint which you use for your write queries. During a failover, RDS routes this endpoint to the new master
- Up to 15 replica
- 2 data flow paths between replicas to ensure replica lag is small and consistent over time
- Aurora writes logs directly to the storage without keeping log buffers. (shared storage volume)
- The replication to the replicas is asynchronous and for only cached data. (asynchronous cache replication)
- Aurora scales faster because
- A new replica can reuse the shared storage volume, can serve queries almost immediately. It doesn’t have to wait to replicate data from the other nodes.
- Aurora does some asynchronous cache replication between nodes, but nothing synchronous. This reduces the inter-node I/O
Provision time over 8 minutes
No public access:
- You can't give an Amazon Aurora Serverless DB cluster a public IP address.
- You can access an Aurora Serverless DB cluster only from within a virtual private cloud (VPC)