Performance in Intel IOMeter: Workstation Pattern

The Workstation pattern emulates the user’s intensive work in various applications in NTFS5.

It’s funny but we found a curious thing in the arrays’ behavior at very low loads – the characteristic ledge in the graph. We saw this ledge when we first reviewed the WD740GD hard disk drive in our article called WD740GD aka Raptor 2 Hard Disk Drive Review .

It’s all normal with the RAID0 array – the more drives it consists of, the faster it is. The performance of the RAID1 is much higher than that of the single drive, while the RAID10 is always, even though by a narrowest margin, faster than the 3-disk RAID0. The RAID5 arrays are not very fast since the Workstation pattern contains many random write requests which negatively affect the performance of RAID5.

We compare the different RAID arrays by calculating their performance rating by the following formula:

Performance = 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.

It was to be expected that the RAID5 arrays would only be faster than the single drive – because of the write requests. The RAID0 arrays rank up according to the number of drives they are comprised of. The mirroring RAID1 and RAID10 take their places right after the RAID0 arrays with the same number of drives.

Let’s see how the controller’s caching policy affects the performance of the arrays in this pattern:

Disabled caching affects the speed of each array negatively – the performance is lower by a third almost.