Failing over Multi-AZ deployment - Amazon Redshift
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Failing over Multi-AZ deployment

Your Multi-AZ data warehouse is a collection compute resources deployed simultaneously in two Availability Zones. The compute resources deployed in the primary Availability Zone are referred to as primary compute and those in the secondary Availability Zones are referred as secondary compute. A Multi-AZ data warehouse can automatically recover without any user intervention during an unlikely event such as an Availability Zone or infrastructure failure. The recovery process involves failing over from primary compute to secondary compute and designating secondary compute resources as primary. Additionally, new secondary compute resources are provisioned in a third Availability Zone. The automatic recovery process is measured in terms of RTO and RPO.

  • Recovery time objective (RTO) — The time it takes a system to return to a working state after a disaster. In other words, RTO measures downtime.

  • Recovery point objective (RPO) — The amount of data that can be lost (measured in time). For an Amazon Redshift Multi-AZ data warehouse, RPO is typically is zero as all the data is stored in Amazon Redshift Managed Storage (RMS), backed by Amazon Simple Storage Service, which is a highly durable and available by default.

Note

The performance of an individual query performance will not change after a failover has occurred. The overall throughput of your data warehouse will be reduced for a short time due to unavailability of compute resources in one of the Availability Zones. However, Amazon Redshift will automatically acquire capacity in another Availability Zone to ensure the same data warehouse processing capacity is restored.

In addition to the automatic recovery process, you can also trigger this process manually for your data warehouse using the Failover primary compute option. You can use this approach to test how Multi-AZ would help your application for higher high availability and better continuity.

  1. Sign in to the Amazon Web Services Management Console and open the Amazon Redshift console at https://console.amazonaws.cn/redshiftv2/.

  2. Do one of the following:

    • On the navigation menu, choose Clusters. Under Clusters, choose a cluster. The cluster details page appears.

    • From the cluster dashboard, choose a cluster.

  3. From Actions, choose Failover primary compute.

  4. When prompted, click Confirm.

  • From the Amazon CLI, use the failover-primary-compute command as follows.

    aws redshift failover-primary-compute 
    --profile maz-test
    --endpoint-url  https://redshift.eu-west-1.amazonaws.com
    --region eu-west-1
    --cluster-identifier test-maz-11

After the above operation is confirmed, Amazon Redshift will perform the same steps as an automatic recovery from an Availability Zone or infrastructure failure. The process will cause compute nodes in the primary Availability Zone to become unavailable and compute resources in the secondary Availability Zone will be designated as primary compute. When the cluster recovery successfully completes, Multi-AZ deployment becomes available. Your Multi-AZ data warehouse will also automatically provision new secondary compute in another third Availability Zone as soon as it is available.

During this process, the cluster status on the console shows as modifying for the entire time, as the cluster automatically recovers and reconfigures back to the Multi-AZ deployment setup. The cluster can accept new connections immediately. Existing connections and inflight queries might be dropped. You can retry them immediately.