AWS DR Anti-Patterns: Avoiding Common Mistakes
Tags: aws, dr, sre, antipatterns
Published: 2023-03-25 05:34:04


Implementing disaster recovery (DR) in the cloud using AWS can be a technically challenging process that requires careful planning and execution. AWS provides a range of DR strategies and services, each with their own strengths and weaknesses. However, there are some common anti-patterns that can hinder the effectiveness and efficiency of these solutions. In this post, I will explore some of these anti-patterns and provide recommendations for avoiding them.

DR is a set of processes and procedures that enable organizations to recover from disasters or unexpected events that disrupt their business operations. The effectiveness of a DR solution is typically measured by two key metrics: 

- Recovery Time Objective (RTO) 
- Recovery Point Objective (RPO).

**RTO** is the maximum acceptable downtime for a system or application before it affects the organization's operations. 
**RPO** is the maximum acceptable data loss in case of a disaster. 

AWS provides several DR types that organizations can leverage to achieve their RTO and RPO objectives. These include:

- **Backup and Restore:** This involves using AWS Backup, a fully managed backup service that centralizes and automates the backup of data across AWS services in the cloud and on-premises environments.
- **Pilot Light:** A pilot light DR approach involves having a minimal version of the application running in the cloud, ready to be expanded in case of a disaster.
- **Warm Standby:** A warm standby DR approach involves having a partially running environment in the cloud, with some resources already up and running but not yet fully functional.
- **Multi-Site:** This involves replicating data and applications across multiple regions, availability zones, or even different cloud providers.
- **Hot Standby:** A hot standby DR approach involves having a fully functional and redundant environment in the cloud that can be immediately used in case of a disaster.
- **Disaster Recovery as a Service (DRaaS):** This is a cloud-based DR solution that provides organizations with a flexible and cost-effective way to protect their IT infrastructure and applications.


Despite the benefits of these DR types, there are common anti-patterns that organizations should avoid when implementing them. These include:

**Backup and Restore:**

- Relying solely on backups for disaster recovery without testing them regularly. Testing backups ensures that critical data and applications can be recovered in case of a disaster.
- Backing up data and applications to the same location or region as the primary site. This can lead to data loss in case of a regional disaster, such as a hurricane or earthquake.

**Pilot Light:**

- Not monitoring the pilot light infrastructure and assuming it will work flawlessly during a disaster. This can lead to unexpected failures during a real disaster.
- Failing to automate the process of scaling up the pilot light infrastructure in case of a disaster. This can result in delays in the recovery process and increased RTO.

**Warm Standby:**

- Not monitoring the partially running environment in the cloud, resulting in unexpected failures or issues during a disaster.
- Not properly synchronizing data between the primary site and the warm standby site, leading to data inconsistencies and the inability to recover data.

**Multi-Site:**

- Not testing the multi-site setup regularly, resulting in unexpected issues during a real disaster.
- Relying solely on multi-site replication for disaster recovery without having a backup plan in case of regional or cloud provider failures.

**Hot Standby:**

- Not testing the hot standby environment regularly, leading to unexpected issues during a real disaster.
- Relying solely on the hot standby environment without having a backup plan in case of cloud provider failures or other external factors.

**Disaster Recovery as a Service (DRaaS):**

- Not fully understanding the DRaaS provider's offerings and not aligning them with the organization's RTO and RPO requirements.
- Failing to test the DRaaS provider's services regularly and assuming they will work flawlessly during a real disaster.

In conclusion, to implement a successful DR strategy in AWS, it is important to avoid the above anti-patterns and follow some best practices. 

Here are some recommendations for implementing an effective DR strategy in AWS:

- Define RTO and RPO: Start by defining the Recovery Time Objective (RTO) and Recovery Point Objective (RPO) for each of your applications. This will help you determine the appropriate DR solution for each application.
- Automate the DR process: Use automation tools like AWS CloudFormation, AWS CodePipeline, and AWS Config to automate the process of setting up and testing your DR infrastructure. This will help you reduce manual errors and improve the speed of recovery.
- Test your DR plan regularly: Test your DR plan regularly to ensure that it works as expected. Use tools like AWS CloudFormation, AWS Config, and AWS CloudTrail to automate the testing process and identify any issues.
- Use a multi-region approach: Use a multi-region approach to replicate data and applications across different regions to protect against regional failures. AWS provides a global infrastructure that spans across multiple regions, making it easy to implement a multi-region approach.
- Use DRaaS: Consider using Disaster Recovery as a Service (DRaaS) to offload the burden of managing your DR infrastructure. DRaaS providers like AWS offer fully managed DR solutions that can help you achieve your RTO and RPO goals.

By following these best practices, you can implement an effective DR strategy in AWS that protects your applications and data from disasters and unexpected events.