Abstract: To minimize the disk array response time for every file access request and improve the disk system I/O throughput,a method to choose the right striping unit was proposed.In this method,files could be divided into two groups in accordance with request arrival rate.For the files accessed frequently,the right striping unit was chosen by meeting the throughput requirement.But for the other files,a auto-adaptive method was presented.Under the same hardware conditions,the choice of striping unit depended on only two parameters: request size and request arrival rate.Moreover,the calculation of the striping unit was also been simplified,then only through a simple formula,the near-optimal striping unit size could be quickly and easily calculated.Theoretical analysis and experimental results indicate that the method has better performance both in time and in space.