Methods and apparatus for cache flush control and write re-ordering in a data storage system are provided. A cache flush control method includes cache flushing information stored in a cache memory to a first storage apparatus of a plurality of storage apparatuses included in a data storage system when a cache flush condition is generated, and performing a write command in a second storage apparatus of the plurality of storage apparatuses which has a write speed lower than the first storage apparatus according to information stored in the first storage apparatus processed with the cache flush.