PURPOSE: A redundant array of inexpensive disk (RAID) memory system is provided to optimize the performance of the RAID memory system by controlling the size of a stripe block. CONSTITUTION: A non-volatile memory device (200) includes a stripe block. A memory controller (100) measures at least one among a program of the stripe block, an erase cycle, and a frequency of reading errors and determines whether or not the size of the stripe block is changed by considering a measured value. The stripe block includes RAID parity. The memory controller changes the size of the stripe block when it is determined that the size of the stripe block is changed.
