EBS Snapshots, Encryption, and RAID Architectures

EBS snapshots

Snapshots are point-in-time backups of EBS volumes. These snapshots occupy the same storage space as the EBS volume, but because they’re stored on S3 in the backend, they cost less. When taking snapshots, we don’t need to stop the EC2 instance or detach a volume, but doing either of these steps is recommended to maintain data integrity.

We can copy snapshots across AWS Regions. Therefore, whenever we want to migrate EBS volumes across AWS Regions, we use snapshots.

EBS snapshot features

Let’s look at some key features of EBS snapshots.

• When creating snapshots of root EBS volumes, stopping the instance is recommended but not required.
• It’s unnecessary to stop the EC2 instance to create a snapshot of its non-root volumes.
• Snapshots only capture data that has been written to our EBS volume at the time the snapshot command is issued.
• We can move our old and infrequently used EBS snapshots to the EBS Snapshot Archive, which is a 75% cheaper method of storage. Note that restoring snapshots from the archive takes 24–72 hours.
• We can set up a recycle bin for EBS snapshots and configure it to store deleted snapshots (for a time range of one day to one year).
• When an EBS volume is restored from a snapshot, there’s a lot of latency. This is because every time we access a new data block in the EBS for the first time, it’s pulled from S3, where the snapshot is stored. We can enable fast snapshots restore (FSR) for EBS snapshots to quickly initialize the entire EBS volume with all the data blocks.