As part of our recent move to Amazon Web Services (AWS) we've implemented a number of new backup/disaster recovery strategies. Here are some of the more important ones:
- Multiple Availability Zones: Our LMS is now replicated across three different availability zones (two in Europe) in the US-East region (EU-West in Europe). Although these zones are located in the same general geographic area, each one is logically separated and completely independent of the others. These zones serve two purposes: requests are distributed across the zones to balance the load on each server, and if one zone should fail requests will immediately be redirected to the other zones.
- Multiple Database Backups: We have three levels of backups for our database:
- Every 15 minutes:A transaction log backup is taken to allow point in time recovery
- Every night: A differential backup is taken that includes all changes made to the database that day.
- Every week: A full database backup is taken.
- Nightly Course Data Backups: All course data is backed up nightly to Amazon's S3 distributed storage service.