Volumes and Snapshots

Volumes

Volumes are virtual hard disks
EC2 instances require at least 1 volume
- Called the root device volume
  - This is where the operating system is installed
Volumes will be in the same availability zone as the EC2 instance they're attached to
Volumes can be resized and volume types can be changed without stopping EC2 instances
- File system may need to be extended

Snapshot of volume (virtual disk)
Stored on S3
Point in time copy of a volume
Snapshots are incremental
- Only data that has changed since the last snaphot is moved to S3
For a consistent snapshot, it is recommended to stop the EC2 instance to take a snapshot
- Snapshots don't include any cached data
If you take a snapshot of an encrypted volume, the snapshot will automatically be encrypted
Snapshots can only be shared in the region they were created in. To share across regions, they need to be copied into the destination region first