Performance in Intel IOMeter File Server & Web Server Patterns

The first pattern imitates the typical load on the disk subsystem of a file server:

The graphs show the correlation between the array speeds and the request queue depth:

The RAID0 arrays are well-scalable in the quantity of disks per array, even at small request queue depths. The read speed of the RAID1 array always coincides with the speed of the single drive, while the speed of the RAID10 with that of the two-disk RAID0. Considering that the File Server pattern has only 20% of write requests, we can suppose that the Sil 3114 controller never uses optimization techniques when reading from a mirror.

We calculate the performance rating for each array by averaging the controller’s speed under each workload:

As you see, there are no surprises here, too. The RAID0 arrays line up according to the number of drives per array. The mirrored arrays – RAID1 and RAID10 – are slightly slower than the single drive and the two-disk RAID0, respectively.

Now, we run the Web Server pattern, which has no write requests at all.

The RAID0 arrays boast good speed scalability depending on the number of disks per array. The speed of the RAID1 array always coincides with that of the JBOD, while the RAID10 is as fast as the two-disk RAID0. Considering that the Web Server pattern with its 100% of writes is ideal for mirrored arrays to show their advantages in, we are now absolutely certain that the Sil 3114 doesn’t optimize reading from mirrors.

We calculate the performance ratings of the arrays in the same way as in the File Server pattern:

The arrays took the same positions in the table as in the File Server pattern. Of course, the RAID10 is higher-performing here than the two-disk RAID0, but the difference is negligible, like in the previous pattern.