Now let’s see what the controller does during sequential writing. The controller data transfer rates depending on the size of the data block are all given in the table below:
Now let’s take a look at the graphs showing the dependence of the array speed on the data block size. The graphs will again split into groups:
Just as in case of Sequential Reading, RAID0 arrays built of multiple HDDs start showing their real advantages only when the requested data blocks are considerably large. However, during reading this array group jumped very rapidly to the maximum level of performance with small requests already, while during writing the speed growth was definitely smoother.
When there are no read requests, the performance of RAID1 and RAID10 mirrored arrays almost coincides with that of a single HDD and a two-drive RAID0 array respectively. RAID5 arrays demonstrate pretty good scalability of performance on the number of hard disk drives in the array and reach their maximum speed at relatively small data blocks already. However, they still cannot reach the maximum speed of RAID0 arrays from n-1.