Performance in Intel IOMeter File- & WebServer Patterns
These are the patterns imitating the work of the file-and webservers.
Although the results in the tables are pretty close, we should still check the graphs, just to make sure we haven’t missed anything.
Mirrored arrays (RAID 1 and RAID 01) perform beautifully fast. RAID 1 array runs almost as fast as RAID 0 array of two drives, except the 16 requests queue depth. This performance drop can be observed in both: WT and WB modes, but in case of enabled WB-caching the performance loss is less severe. RAID 01 outperforms all other arrays, except RAID 0 of four drives, and when the queue is 4 or 16 requests deep, then it shows its real best.
Let’s apply our great rating system to compare the performance of RAID arrays of different types with one another. Assuming that all the workloads are equally probable, we will calculate the rating as average performance under all types of workload:
RAID 0 array of four drives managed to retain the performance leadership only because FileServer pattern carries some writes, which are usually processed faster on RAID 0 than on RAID 01. RAID 1 array fell behind RAID 0 of two HDDs because of the same 20% of writes, even though the graphs of these two arrays were almost coinciding. Besides, the rating system demonstrates that even so few writes are more than enough to boost the performance in case of enabled WB-caching.