Volumes Support Articles

No; however, you can add another layer onto your Droplet with an attached Volume.
Adding a volume to your Droplet doesn’t increase its main disk size. You need to resize the Droplet to increase its main disk size.
Filesystem tools often don’t report the capacity reserved for metadata and the root user, and some report size in different units.
Snapshots of Droplets are a best estimate based on the disk usage. Snapshots of volumes operate at the block storage level, so the snapshot size may not match what the filesystem reports.
You cannot currently download DigitalOcean backups or snapshots, but you can use third-party tools to save your data locally.