Writing comes next.
This diagram usually shows scalability according to the principle “the more disks and the more cache, the higher the resulting performance is”. The LSI controller has it in its own way: the 8-disk RAID10 behave oddly, slowing down on every small-size data block excepting the smallest one (512 bytes). As a result, they are occasionally slower than the 4-disk array! However, the 4-disk RAID0 is even worse: its speed is no higher than that of the single HDD. At the same time, the 8-disk RAID0 and the 4-disk RAID10 show a normal performance.
The rotated parity arrays are all right. The graphs are indicative of proper scalability but the controller still lacks cache memory to be competitive to the opponent products we have tested before.
The arrays go on behaving oddly when writing in large data blocks. This time the 8-disk RAID10 (both healthy and degraded) are good whereas the 8-disk RAID0 depends too much on the size of the data chunk. Particularly, it shows a strong dislike of 512KB data chunks. The 4-disk RAID0 is slower at writing than the single HDD, and the 4-disk RAID10 is not much better, either.
The RAID6 arrays show problems when writing in large data blocks. The speed is too low, except for the degraded RAID6 with one failed disk.