Disaster recovery in the cloud options

These are by all means not all the options, but at a high level these are the common options:

• Backup and restore - Have to set up security groups set up and set up Route53. Data is not being mirrored or replication. You are doing an import and export from database to S3. When system goes down then resource S3 data to the database. You also have to provision AMIs.
• Pilot light – In this case, you are doing Data mirroring/replication from source system to DR site. Could run GoldenGate. The EC2 instances are present but stopped. Have to prepare all required resources from automatic start – AMIS, network settings, load balancing etc.
• Fully working low capacity standby – Blurring lines between HA and DR. In this case have an issue with RDS as the data needs to replicated both ways as traffic could go to either configuration.
• Multi-site hot standby – production load on both sides. Cost and data sync are the biggest challenges.

AWS Four DR scenarios

There are four DR scenarios that highlight usage of AWS in a DR and a 'HA-lite' situation:

•  Backup and Restore - For systems running on AWS, customers also back up into Amazon S3. Snapshots of Elastic Block Store (EBS) volumes and backups of Amazon RDS are stored in Amazon S3. Alternatively, you can copy files directly into Amazon S3, or you can choose to create backup files and copy them to Amazon S3.
• Pilot Light for Simple Recovery into AWS - This scenario is similar to a Backup and Restore scenario, however, you must ensure that you have the most critical core elements of your system already configured and running in AWS (the pilot light). When the time comes for recovery, you would then rapidly provision a full scale production environment around the critical core. The database data would be replicated to S3. You would typically have some pre-configured servers bundled as Amazon Machine Images (AMIs), which are ready to be started up at a moment’s notice.  These servers could be EC2 instances that have been stopped.
• Warm Standby Solution - A warm standby solution extends the pilot light elements and preparation. It further decreases the recovery time because in this case, some services are always running. By identifying your business-critical systems, you would fully duplicate these systems on in another AWS zone or region and have them always on.  This would insure that the EC2 capacity is available in a disaster.
•  Active-Active Solution - A multi-site solution runs in another AZ or zone in an active-active configuration. The data replication method that you employ will be determined by the recovery point (RPO) you choose.