claytran
commented
1 year ago The doc currently says:
If the DB cluster doesn't contain any Aurora Replicas, then the primary instance is recreated in the same AZ during a failure event. A failure event results in an interruption during which read and write operations fail with an exception. Service is restored when the new primary instance is created, which typically takes less than 10 minutes. Promoting an Aurora Replica to the primary instance is much faster than creating a new primary instance.
Suppose that the primary instance in your cluster is unavailable because of an outage that affects an entire AZ. In this case, the way to bring a new primary instance online depends on whether your cluster uses a Multi-AZ configuration:
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If your provisioned or Aurora Serverless v2 cluster contains any reader instances in other AZs, Aurora uses the failover mechanism to promote one of those reader instances to be the new primary instance.
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If your provisioned or Aurora Serverless v2 cluster only contains a single DB instance, or if the primary instance and all reader instances are in the same AZ, make sure to manually create one or more new DB instances in another AZ.
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If your cluster uses Aurora Serverless v1, Aurora automatically creates a new DB instance in another AZ. However, this process involves a host replacement and thus takes longer than a failover.
The FAQs are crystal clear: it takes up to 15 minutes to recover if the restored instance must be created in another AZ. On the other hand, the documentation doesn't specify to which case the 10 minutes applies to, leaving the reader to assume that it must be within the same AZ. See the excerpts below.
Aurora FAQs: "If you do not have an Amazon Aurora Replica (i.e. single instance), Aurora will first attempt to create a new DB Instance in the same Availability Zone as the original instance. If unable to do so, Aurora will attempt to create a new DB Instance in a different Availability Zone. From start to finish, failover typically completes in under 15 minutes".
Documentation: "If the DB cluster doesn't contain any Aurora Replicas, then the primary instance is recreated during a failure event. A failure event results in an interruption during which read and write operations fail with an exception. Service is restored when the new primary instance is created, which typically takes less than 10 minutes."