However trivial this may sound, we have to say that there are no perfect things in this imperfect world. When it comes to hardware, every controller has its highs and lows and you should take into account that some controllers suit better for certain loads than others. You should also be aware that firmware can dramatically change a controller’s behavior. We will now name the winners and losers of this test session basing only on the performance the controllers deliver with their current firmware.
The Adaptec RAID ASR-5805 and Areca-1680x-16 leave the best overall impression. These two models passed our tests in a stable manner, showing fewer flaws in their firmware algorithms. The Adaptec is overall somewhat better for databases whereas the Areca is superior at multithreaded operations and at processing files. In any case, both are worthy representatives of today’s SAS RAID controller generation. Interestingly, both are based on very similar platforms. They are equipped with the same processor and have the same amount of onboard memory.
Yes, the Areca allows upgrading its memory but our tests have not revealed any benefits from the larger amount. On the contrary, the 2GB version would often prove to be a little slower. As we have written above, 2GB of cache memory may come in handy when there are a lot of disks connected to this controller via expanders and the interface bandwidth is not high enough to fully satisfy all of them.
The 3ware 9690SA-8I and the HighPoint RocketRAID HPT4320 are good but not without a blemish. The former would be a very good controller if it were not for its low performance with files. Thus, it is better suited for database applications in which it will show itself as a balanced and powerful device. The HighPoint has excellent RAID10 algorithms and very good writing, but it has too many problems with checksum-based arrays. Hopefully, these problems will have been solved in the next versions of its firmware and the choice of good controllers will be broader then.
The LSI MegaRAID SAS 8708EM2 and Promise SuperTrak EX8650 are somewhat disappointing. Of course, the Promise was handicapped in our tests due to the lack of deferred writing, but its reading performance was often too slow in comparison with its opponents, too. The LSI has too many flaws although its processing of small files and the excellent algorithm of selecting the luckier disk in a mirror pair are impressive. Still, firmware is improving, so every controller actually has a chance to get better. On the other hand, the existing infrastructure of specific-brand controllers is often a more important factor for making shopping decisions unless performance is downright poor.