Amazon Glacier is very low cost storage service that provides durable, secure and flexible storage for data archiving and online backups. It is mostly used for infrequent accessed data and its retrieval time is three to five hours.
It has following features:
In Amazon Glacier data is stored in archives, and it contain up to 40 TB of data. Each archive has unique archive ID at the time of creation. All Archive are automatically encrypted and cannot be modified.