Disaster recovery (DR) is the process of preparing for and recovering from a disaster that can affect your workload on AWS. A disaster can be a natural event, such as an earthquake or a flood, a technical failure, such as a power outage or a network issue, or a human action, such as an accidental or malicious modification. The main objectives of DR are to minimize downtime and data loss, and to restore normal operations as quickly as possible.

To achieve these objectives, you need to define your recovery time objective (RTO) and recovery point objective (RPO) for your workload. RTO is the maximum acceptable delay between the interruption of service and restoration of service. RPO is the maximum acceptable amount of time since the last data recovery point. Depending on your workload requirements and budget, you can choose different DR strategies that provide different levels of RTO and RPO.

AWS offers various DR options in the cloud that can help you protect your workload from disaster events. These options can be broadly categorized into four approaches:

Backup and restore

This is a suitable approach for mitigating against data loss or corruption. You can use AWS services such as Amazon S3, Amazon EBS, AWS Backup, and AWS Storage Gateway to back up your data to the cloud. You can also use AWS services such as AWS CloudFormation, AWS Cloud Development Kit (AWS CDK), and AWS CodePipeline to back up your infrastructure, configuration, and application code to the cloud. In case of a disaster, you can restore your data and redeploy your infrastructure in the same or another AWS Region.

Pilot light

This is an approach that uses an active site (such as an AWS Region) to host the workload and serve traffic, and a passive site (such as a different AWS Region) to host a minimal version of the workload that is always running but not serving traffic. The passive site contains only the core elements of the workload, such as the database and some application servers. In case of a disaster, you can quickly scale up the resources in the passive site and switch the traffic to it.

Warm standby

This is an approach that uses an active site (such as an AWS Region) to host the workload and serve traffic, and a passive site (such as a different AWS Region) to host a scaled-down version of the workload that is always running and serving a small amount of traffic. The passive site contains most of the elements of the workload, such as the database, application servers, web servers, and load balancers. In case of a disaster, you can quickly scale up the resources in the passive site and switch the traffic to it.

Multi-site active/active

This is an approach that uses multiple active sites (such as different AWS Regions) to host the workload and serve traffic simultaneously. The active sites are synchronized using data replication and load balancing techniques. In case of a disaster, you can redirect the traffic from the affected site to the other sites.

To choose the best DR option for your workload, you should consider factors such as your RTO and RPO requirements, your workload characteristics, your operational complexity, and your cost. You should also test your DR strategy regularly using tools such as AWS Resilience Hub to validate and track the resilience of your workload.