EBS Snapshots

• You can back up the data on your EBS volumes to Amazon S3 by taking point-in-time snapshots.

• Snapshots are incremental backups - this means that only the blocks on the device that have changed after your most recent snapshot are saved.

  • This minimizes the time required to create the snapshot and saves on storage costs by not duplicating data.

  • Each snapshot contains all of the information that is needed to restore your data (from the moment when the snapshot was taken) to a new EBS volume.

• When you create an EBS volume based on a snapshot, the new volume begins as an exact replica of the original volume that was used to create the snapshot.

  • The replicated volume loads data in the background so that you can begin using it immediately.

  • If you access data that hasn't been loaded yet, the volume immediately downloads the requested data from Amazon S3, and then continues loading the rest of the volume's data in the background.

Copying and sharing snapshots

• A snapshot is constrained to the AWS Region where it was created.

  • After you create a snapshot of an EBS volume, you can use it to create new volumes in the same Region.

• You can copy snapshots across Regions, making it possible to use multiple Regions for geographical expansion, data centre migration, and disaster recovery.

Restoring an EBS volume

• Try to automate and test the restore process as much as possible to reduce the risk of your restore process failing or being implemented inconsistently.

• Data from an Amazon EBS snapshot is asynchronously loaded into an EBS volume.

• If an application accesses the volume where the data is not loaded, there is higher latency than normal while the data is loaded from Amazon S3.

  • To avoid this impact for latency-sensitive applications, you can pre-warm your data from a snapshot into an EBS volume.

• You can restore a non-root volume attached to an existing EC2 instance by creating a volume from a snapshot and attaching it to your instance.

  • You can then mount the volume to the instance by using the operating system.

Amazon Data Lifecycle Manager (DLM)

• Amazon DLM for EBS Snapshots provides a simple, automated way to back up data stored on Amazon EBS volumes.

• You can define backup and retention schedules for EBS snapshots by creating lifecycle policies based on tags.

  • You no longer have to rely on custom scripts to create and manage your backups.