Understanding Disaster Recovery:
Data security must be taken seriously due to the increasing number of cyber-attacks, malware, and viruses that are moving online. There are some critical systems that must be available to every business. Every organization should have a Business Continuity Plan. This plan is used to protect the business from potential threats. To minimize the impact on software applications, a Disaster Recovery Plan is a subset the Business Continuity Plan.
Disaster Recovery (DR), is the process that an organization uses to regain access to their application or data in order to resume critical business functions following an event such as a natural disaster or a human-driven catastrophe. Your ability to replicate your IT systems, and data, is crucial in ensuring that your application remains available in the event of a disaster. The disaster recovery plan outlines how a company will prepare for a disaster and what the response would be. It also outlines what steps would be taken in order to restore normal operations.
Amazon Web Services (AWS), a leading cloud service provider, has provided 4 methods for disaster recovery preparation. Each technique can be used in specific situations.

The Backup & Restore Strategy is the first. I discussed that in my previous blog, Understanding the Vitality and Disaster Recovery Plans in an Organization.
This blog will show you how the Pilot Light strategy works and how to plan for Pilot Light recovery.
Introducing Pilot Light:
AWS offers four types of Disaster Recovery options. The benefits of RTO and RPO can be used to help you choose the right DR strategy.
This strategy is known as a Quick Recovery Strategy. It ensures that critical components of the systems are configured and running in AWS Pilot Light. The DR team would quickly provision a production environment in case of an emergency. The team should weigh the costs of implementation and operation against the benefits of a lower RTO (Recovery Time Obligation) and RPO [Recovery Point Obligation].
Are you confused about RTO or RPO? Here’s a quick explanation.
Recovery Point Objective: RPO stands for Recovery Point Objective. It is the maximum acceptable time period since the last data recovery point. This is the acceptable data loss between the last recovery point (or interruption of service).
Recovery Time Objective: RTO stands for the maximum delay between interruption of service and restoration. This is the acceptable time frame for service interruptions.

The Recovery using the Pilot Light Technique offers 10s of minutes RTO and RPO. The Pilot Light Strategy replicates data in the primary region to the recovery region’s data resources, such as Amazon RDS instances and Amazon DynamoDB databases. These resources are available to serve requests. You will need to create a backup in the recovery area.
Architecture Diagram:
The primary Region active in AWS is the left side, while the recovery Region passive in AWS is the right.

AWS Services that can also be used to provide Pilot Light DR Solution
AWS EC2 instance
Amazon S3
Amazon Glacier
AWS Storage Gateway
AWS Direct Connect
AWS Custom Software Packages
Amazon Machine Image (AMI).
Route 53
Elastic load balance
Pilot Light failover mechanism
Pilot Light DR allows you to run a minimal version in the cloud, which hosts the critical functionality of your application. A full-scale production environment can quickly be provisioned around the critical core during recovery.
The operational level agreement (OLA), which defines the RTO/RPO, can help us to determine when we should use the Pilot Light DR.

AWS Pilot Light Part II – An Automated Disaster Recovery System