What does AWS use when you copy an instance store–backed AMI to a different region?

What does AWS use when you copy an instance store–backed AMI to a different region?

• EFS
• EBS
• S3
• Glacier

Explanation

When you copy an instance store–backed Amazon Machine Image (AMI) to a region, you create an Amazon S3 bucket for the AMIs copied to that region. All instance store–backed AMIs that you copy to that region are stored in this bucket. The bucket names have the format amis-for-account-in-region-hash (for example, amis-for-123456789012-in-us-east-2-yhjmxvp6).

You can copy an Amazon Machine Image (AMI) within or across AWS Regions. You can copy both Amazon EBS-backed AMIs and instance-store-backed AMIs. You can copy AMIs with encrypted snapshots and also change encryption status during the copy process. You can copy AMIs that are shared with you.

Copying a source AMI results in an identical but distinct target AMI with its own unique identifier. You can change or deregister the source AMI with no effect on the target AMI. The reverse is also true.

With an Amazon EBS-backed AMI, each of its backing snapshots is copied to an identical but distinct target snapshot. If you copy an AMI to a new Region, the snapshots are complete (non-incremental) copies. If you encrypt unencrypted backing snapshots or encrypt them to a new KMS key, the snapshots are complete (non-incremental) copies. Subsequent copy operations of an AMI result in incremental copies of the backing snapshots.

Source

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/CopyingAMIs.html