BACKGROUND

Object storage is a data storage model that manages data in the form of logical containers known as objects, rather than in the form of files (as in file storage) or blocks (as in block storage). Cloud object storage is an implementation of object storage that maintains these objects on a cloud infrastructure, which is a server infrastructure that is accessible via the Internet. Due to its high scalability, high durability, and relatively low cost, cloud object storage is commonly used by companies to backup large volumes of data for disaster recovery and long-term retention/archival.

Several cloud object storage platforms such as Amazon Simple Storage Service (S3), Microsoft Azure Blob Storage, and the like offer at least two different storage tiers to customers: (1) a “standard” storage tier that is the default storage tier of the platform and is intended for data which may be accessed frequently, and (2) a “cold” storage tier that is intended for data which is seldom accessed (e.g., on a semi-annual basis or less). The main benefit of the cold storage tier over the standard storage tier is lower storage cost; for example, in the case of Amazon S3, its cheapest cold storage tier (known as “glacier deep archive”) is 23 times less expensive per gigabyte (GB) than its standard storage tier. However, because the cold storage tier is designed to store infrequently accessed data, the latency for retrieving data maintained in this tier and the application programming interface (API) cost for invoking each retrieval operation is significantly higher. In addition, many cloud object storage providers impose a “minimum storage duration” on cold storage tier data, which means that any data kept in the cold storage tier for a time period shorter than this duration will incur an early deletion fee equal to the storage charge for the remaining days of the minimum storage duration.

