Combined Asynchronous and Synchronous Fountain Code Storage In an Object Store

摘要

Example apparatus and methods produce a set of rateless erasure codes (e.g., fountain codes) for a file stored in a primary data store (e.g., hard drive) or in an archive system. The archive system may store the file in a redundant array of independent disks (RAID). A first subset of the rateless erasure codes are stored in an object storage using a synchronous protocol. A second subset of rateless erasure codes are stored in the object storage using an asynchronous protocol. The object storage system may inform the archive system when desired redundancy has been achieved or when desired redundancy has been lost. The archive system may buffer rateless erasure codes before providing the codes to the object storage to improve performance. A failure in the archive system or object storage system may be mitigated by retaining the file in the primary data store until the desired redundancy is achieved.

主权项

1. A non-transitory computer-readable storage medium storing computer-executable instructions that when executed by a computer cause the computer to perform a method, the method comprising:
receiving a request to increase the redundancy level of a file stored in a first data store; producing a number of rateless erasure codes to be provided from a second data store to a third data store to increase the redundancy level of the file, where the number of rateless erasure codes is controlled by a redundancy policy, where the redundancy policy identifies a total number of rateless erasure codes to be stored and a minimum number of rateless erasure codes to be stored, where the minimum number is less than the total number; providing the minimum number of rateless erasure codes to the third data store using a synchronous approach; determining a remaining number of rateless erasure codes equal to the difference between the total number and the minimum number; upon determining that the minimum number of rateless erasure codes have been stored in the third data store:
providing the remaining number of rateless erasure codes to the third data store using an asynchronous approach; and upon determining that the total number of rateless erasure codes have been stored by the third data store, sending a signal to the first data store indicating that the total number of rateless erasure codes have been stored in the third data store.