To follow up @Andrew's imagination:
Amazon annouced "an option that will allow customers to seamlessly move data between Amazon S3 and Amazon Glacier" (http://aws.amazon.com/en/glacier/faqs/#How_should_I_choose_between_Amazon_Glacier_and_Amazon_S3)
In case there is an API for it - duplicty could alternatively store the complete backup in S3 and then moves the data to Glacier.
To follow up @Andrew's imagination:
Amazon annouced "an option that will allow customers to seamlessly move data between Amazon S3 and Amazon Glacier" (http:// aws.amazon. com/en/ glacier/ faqs/#How_ should_ I_choose_ between_ Amazon_ Glacier_ and_Amazon_ S3)
In case there is an API for it - duplicty could alternatively store the complete backup in S3 and then moves the data to Glacier.