IOZone performance
Let the benchmarking commence. We'll start with IOZone.
We must stress that IOZone is a file system test and not solely a disk test, so caching and other optimisations play a big role in the results. However, the surface graphs all follow the same contours. Note the change in scale on the second two graphs as RAID boosts the throughput.
The area towards the right of the graph (where the file size is particularly large) is indicative of disk or array performance. Note the undulations. We experienced fluctuating read/write results using HD Tach, too. Whatever causes it, it seems to be at the disk level or its interface. Although it's hard to see from the scale, write performance isn't looking all that good in RAID-5. RAID-0 is better, but not leaps ahead of a single disk.
Thoughts on these results? Write performance doesn't look promising, but if data's cached, hold on to your pants.
