Performance in Intel IOMeter Workstation Pattern

The Workstation pattern imitates intensive work of a user in various applications in the NTFS5 file system. The results for the write-through and write-back modes are as follows:

The graphs show the dependence of the speed on the request queue depth:

The RAID0 arrays reach their maximum speeds at small queue depths, but only two- and three-disk arrays are scalable from the number of disks per array. The maximum speed of the four-disk RAID0 is just little higher than that of the three-disk RAID0. The speed of the RAID10 is similar and sometimes higher than the speed of the four-disk RAID0. The RAID1 is always faster than the single drive, even considering the performance loss at 2+ request queue depths. The speeds of the RAID5 arrays are the same in the write-through mode – that’s a kind of tradition for the FastTRAK S150 SX4 controller.

After enabling the lazy write, we make the four-disk RAID0 perform faster, but it still doesn’t fit into the scale of the two- and three-disk RAID0s. The four-disk RAID5 is slower than the three-disk RAID5 at requests queue depths of 4 and smaller, but faster than that at bigger depths.

We calculate the performance rating for the Workstation pattern by the following formula:

Performance Rating = Total I/O (queue=1)/1 + Total I/O (queue=2)/2 + Total I/O (queue=4)/4 + Total I/O (queue=8)/8 + Total I/O (queue=16)/16 + Total I/O (queue=32)/32

The four-disk RAID5 took the last place, because of the high percentage of writes and a high probability of short requests. The three-disk RAID5 was faster than the single drive due to the relatively high speed on short requests. For the same reason, RAID1 and RAID10 outperformed RAID0s of the same number of disks.