Now let’s once again resort to our rating system calculated according to the same formula as in FileServer pattern:

Just like in the previous pattern, the single hard disk drive is the slowest, while the situation in the leading group has become slightly different. 100% share of reads makes RAID10 arrays faster than RAID1 arrays of the same number of hard drives.

Now let’s look at the results of four-hard-disk arrays obtained with different types of caching algorithms enabled:

In fact, the type of controller caching enabled may not affect the performance at all if there are no write requests in the queue. This is what we see by RAID5 and RAID0 arrays. However, RAID10 slows down by half once the controller cache is disabled. We have already seen exactly the same strange phenomenon in the DataBase pattern. Therefore, we dare suppose that in RAID10 array the controller doesn’t switch between WriteBack and WriteThrough modes correctly.