Amazon S3 Glacier is a secure, and extremely low-cost storage class for data archiving and long-term backup.
SimpleBackups allows you to store your files and database backups on S3 Glacier.
All you need to do is connect your S3 storage as usual to SimpleBackups, no other configuration is needed on AWS side.
Create a backup and choose your S3 bucket as the backup storage option
Save your backup then go to the "Advanced" tab.
You will see the following box, click on "Switch to S3 Glacier storage"
When using S3 Glacier, you can only retrieve your backup from S3 console. This is because the retrieval of a Glacier object is not instant and is usually available after a download is requested by a little while.