About Backup Types - AMIs and Snapshots
This article provides an overview of the types of automated backups we provide for Amazon Web Services (AWS) users.
Native Amazon EBS snapshots
We perform native Amazon EBS snapshots, they are incremental by nature. AWS automatically only take incremental changes for each snapshot after that.
The first snapshot is a full copy of the volume; ongoing snapshots store incremental block-level changes only. This is a fast and reliable way to restore full volume data.
Amazon EBS provides the ability to create snapshots (backups) of any Amazon EBS volume. It takes a copy of the volume and places it in Amazon S3, where it is stored redundantly in multiple Availability Zones.
A point-in-time snapshot of an Amazon EBS volume, can be used as a baseline for new volumes or for data backup. If you make periodic snapshots of a volume, the snapshots are incremental—only the blocks on the device that have changed after your last snapshot are saved in the new snapshot. Even though snapshots are saved incrementally, the snapshot deletion process is designed so that you need to retain only the most recent snapshot in order to restore the entire volume.
Where are backups stored?
Your Amazon EBS snapshots are stored in Amazon S3. However, you won't find your snapshots in any of your S3 buckets. AWS uses the S3 infrastructure to store your Amazon EBS snapshots, but you cannot access them while they reside in S3.
Amazon Machine Images (AMI)
You can also automate Amazon Machine Images (AMI) backups as well. An AMI is a template that contains a software configuration (for example, an operating system, an application server, and applications).
From an AMI, you launch an instance, which is a copy of the AMI running as a virtual server in the cloud. Whereas for snapshots you can back up the data on your EBS volumes to Amazon S3 by taking point-in-time snapshots. Snapshots are incremental backups, which means that only the blocks on the device that have changed after your most recent snapshot are saved. When you delete a snapshot, only the data exclusive to that snapshot is removed.