METHOD FOR STORING PARITY AND RECOVERING ERROR BLOCK ON EXTERNAL SUB STORAGE SYSTEM

摘要

PURPOSE: A method for storing a parity and recovering an error block on an external sub storage system is provided to enable the error recovery even if more than three error blocks are generated in the same parity group. CONSTITUTION: A number of the blocks respectively used as a data block and a parity block is decided from the total storage block of disks(S1). A 3-dimensional block matrix formed by the virtual data block on an X/Y/Z coordinates system is constructed by matching with the number of the data blocks(S2). A virtual parity block is assigned to each block plane of the block matrix from an X/Y/Z direction(S3). The virtual data block and the virtual parity block are respectively assigned to the storage blocks in the disk(S4). A parity value is found out based on a data value of the storage blocks matched with the virtual block in the block plane(S5). The parity value is stored to the storage block to store the virtual parity block for the corresponding block plane(S6).