Performance in Intel IOMeter File- and WebServer Patterns

The more hard disk drives form an array, the faster it processes requests. Though, I noticed that an array of four drives is sometimes a little slow…

RAID 5 array of four drives is slightly slower than RAID 10, and RAID 5 of three drives is even slower than RAID 1.

Since FileServer pattern works with about 20% of writes, the performance in it doesn’t depend on the lazy writing algorithms that much. On the other hand, the cache of Intel SRCS14L controller has definitely contributed to lowering the performance differences, which is especially noticeable in the end points of the graph.

To compare the performance of various RAID arrays we suggest using the rating system. Considering all workloads are equally probable, we will calculate the rating coefficient as the average controller performance under all types of workload:

The arrays using mirroring, namely RAID 1 and RAID 10, demonstrate excellent results, as we can see. RAID 10 array outperformed RAID 0 of three HDDs. RAID 0 of four HDDs managed to retain its leadership only due to the fact that there is a certain amount of writes in the FileServer pattern, which are performed faster by RAID 0 array rather than by RAID 10 array. RAID 5 of N HDDs falls behind RAID 0 of N-1 HDDs because of the same 20% of writes.