Amazon Glacier is the lowest cost-per-GB storage system, designed for the explicit purpose of long-term storage and archiving. The data has the same durability characteristics as S3, supports data encryption in transit, and automatically encrypts all data at rest with the 256-bit Advanced Encryption Standard (AES-256). Glacier ties in to the life cycle policies provided by S3, thus giving us the ability to archive data that is no longer needed to be accessed frequently from S3 or infrequently from S3-IA. With our previous example, the data would reside in S3 while it's less than 30 days old, then be migrated to S3-IA up until it is 90 days old, and then we can set it to be automatically sent to Glacier and stored as long as our compliance requirements need us to store that data for.

Once archived, if data needs to be accessed from Glacier there are several ways to request the data from Glacier. The standard request to Glacier will deliver the data within 3-5 hours, but if the data is needed as soon as possible, we can issue an expedited request, which can deliver the same data within 1-5 minutes. There is however limit per size of the request of 250 MB. The data retrieval rates for these two options differ as the expedited request is three times more expensive than a standard request per GB of data. We also have the ability to issue a bulk request; this is the lower cost option, usually costing 25% of a standard request per GB, and is intended for retrieving very large amounts of data. Bulk requests usually take 5-12 hours to deliver the data.