March 19, 2021
An EBS Snapshot is a copy of an EBS volume at a particular point in time.
A snapshot can be taken of a volume, regardless of whether or not the volume is attached to a running instance. A snapshot comprises data blocks that are incrementally saved to Simple Storage Service (S3), meaning that only the blocks on the device that have changed since your last snapshot are saved. When saved to S3, the snapshot is assigned a timestamp and unique AWS ID.
It is crucial to back up your EBS volumes with EBS snapshots, to prevent losing important data.
It is best practice to have at least one backup snapshot per volume. It is especially recommended that you take periodic snapshots when running a DB.