Described is a system (and method) for efficient access-based reallocation of backup data stored within an object storage. The system may implement various specialized procedures to efficiently store and manage backup data within the object storage. These procedures may include packing backup data into objects to improve data operation efficiency. The system may also conserve storage space on the object storage by performing an analysis to reallocate backup data as necessary. For example, data may be stored in objects in an immutable manner, and thus, the system may efficiently reallocate data to new objects based on data access patterns. For example, the system may determine an access pattern associated with live data remaining within the first object satisfies a condition, and in response, reallocated the live data to a new object.