Example implementations relate to data storage. An example includes a method comprising: receiving a data stream to be stored in a persistent storage of a deduplication storage system; assigning new data units to container indexes; storing the new data units of the data stream in a plurality of intake buffers, where each new data unit is stored in the intake buffer associated with the container index it is assigned to; determining whether a cumulative amount stored in the plurality of intake buffers exceeds a first threshold; in response to a determination that the cumulative amount exceeds the first threshold, determining a least recently updated intake buffer of the plurality of intake buffers; generating a first container entity group object comprising a set of data units stored in the least recently updated intake buffer; and writing the first container entity group object from memory to the persistent storage.