Now let’s take a look at the performance of our RAID 1 disk drive array:
The graph showing the performance of the disk drive array with queue=1, we see almost the same picture as in case of RAID 0. The performance is very close to what we have already seen, and the influence of two controller pairs is also similar. The duet from Promise looks more efficient when the share of writes is not that big yet and starts yielding to ITE IT8212F and VIA VT6410 controllers when the writes share reaches 70%.
The increase in the queue depth to 16 requests leads to array performance increase with all controllers. The most noticeable improvement takes place by Promise controllers: RAID array runs fastest of all in case of 100% reads, and then its performance starts going down as the share of writes increases. As soon as disk drive array starts processing only write requests, ITE IT8212F and VIA VT6410 controllers take the lead in terms of efficiency.
The most extraordinary situation with RAID array participating in our test session happen when it was working with 256 request queue: the performance grew up in all four cases compared to the previous graph. Again we see the controller run in pairs. The two solutions from Promise let the array show its best when we had no writes involved at all, then the performance starts going down, however it turns back towards improvement when the writes share reaches 90%. ITE IT8212F and VIA VT6410 controllers appeared highly efficient almost only with write requests.