In a data access method, after an interface card receives a first data write instruction or a first data read instruction, the interface card generates a second data write instruction or a second data read instruction, and writes the second data write instruction or the second data read instruction into a cache. No resource of a processor of a storage device is used. After the interface card writes the second data write instruction or the second data read instruction into the cache, a cache control unit sends the second data write instruction or the second data read instruction to a storage subsystem. No resource of the processor of the storage device is used. Alternatively, the cache control unit may instruct the storage subsystem to execute the second data write instruction or the second data read instruction.