RDS MySQL是否仍支持级联只读副本？
Great question—this is a super common gotcha lately with AWS RDS MySQL! Let’s break down what’s going on here:
First, a quick correction: MySQL doesn’t have a 5.8 version—you’re almost certainly working with MySQL 8.0, which is the current supported major release. That detail matters because AWS has made targeted changes to replica support across different MySQL versions.
You’re not making an operation mistake: The "Create Read Replica" option being disabled for your primary read replica is intentional. AWS has phased out support for secondary read replicas (read replicas of read replicas) for RDS MySQL 8.0 instances. This isn’t a bug—it’s a product strategy shift.
Why the change? AWS is actively guiding users toward Amazon Aurora for workloads needing scalable, multi-tier read replica setups. Aurora was built from the ground up to handle hierarchical replicas (including cross-region ones) far more efficiently than standard RDS MySQL, with better performance and fault tolerance.
The outdated FAQ catch: You’re right that the old RDS FAQ still mentions secondary replica support for RDS MySQL—but documentation often lags behind actual product changes. If you try creating a secondary replica via the AWS CLI with a command like
aws rds create-db-instance-read-replica --source-db-instance-identifier your-primary-read-replica --db-instance-identifier your-secondary-replica, you’ll get a clear error message confirming the feature is restricted for MySQL 8.0.
Alternative Solutions
If you need multi-tier read replicas for your workload:
- Migrate to Aurora MySQL: This is the recommended path—Aurora fully supports secondary (and even tertiary) read replicas, plus offers features like auto-scaling replicas and faster replication.
- Stick with MySQL 5.7: If downgrading is feasible (note: MySQL 5.7 reaches end-of-life in October 2023, so this is only a short-term fix), secondary replicas are still supported for 5.7 instances.
内容的提问来源于stack exchange，提问作者Mart
