Here are the controllers we are going to compare today:
- LSI 3ware 9690SA-8I with the unified software pack version 9.5.1
- Adaptec RAID ASR-5805 with firmware 5.2.0 build 16116 and driver version 184.108.40.20628
- Areca ARC-1680ix-16 with firmware 1.46 and driver version 20.0.14
- HighPoint RocketRAID HPT4320 with firmware 220.127.116.11 and driver version 18.104.22.168
- LSI MegaRAID SAS 8708EM2 with firmware 9.1.1-0013 and driver version 22.214.171.124
- Promise SuperTrak EX8650 with firmware SR1 1.04 and driver version SR1
You can click the links to read a detailed review of the specific controller, so we will only give you a brief description here. Unification seems to be the main trend among the manufacturers. They produce RAID controllers in large series with unified design, the specific models differing only in the number of ports, amount of onboard memory and processor frequency. The latter parameter does not vary much, though. Four out of these six models are equipped with Intel’s dual-core IOP81348: the controllers from Areca, Adaptec and HighPoint use a 1.2GHz version whereas the Promise uses an 800MHz version of the processor. 3ware and LSI keep to their own solutions: the 3ware controller uses a 266MHz AMCC Power PC405CR and the LSI uses an LSISAS1078 (with the PowerPC architecture as well) clocked at 500MHz.
The considerable reduction in RAM prices allows installing more memory on controllers: the LSI has 128 megabytes, the HighPoint and Promise, 256 megabytes. The other controllers have as much as 512 megabytes of onboard RAM.
Moreover, the memory of the Areca controller is not soldered to its PCB but installed as a separate module. Therefore we tested this controller twice: with its default 512MB memory and with a 2GB module. You’ll be surprised to see the results.
All the controllers support most popular RAID levels including 2-layer ones like RAID50. There are only minor differences that can hardly concern general users (e.g. some controllers support RAID3 while others do not support RAID1E). Each of the six controllers has drivers for different operating systems. Each of them boasts an advanced OS-based management and monitoring system. All such systems use networking protocols to provide interaction not only with local but also with remote (located on other computers) controllers. By the way, it is the existing infrastructure that often determines the choice of the controller brand for building a new subsystem. It is much better to have a handy and centralized management system than to support equipment from multiple brands simultaneously.
All of these controllers also support a battery backup unit and we strongly recommend using one. Its cost is usually incomparably lower than the cost of data stored on the RAID which may get lost in case of a power failure if deferred writing is turned on. What happens if deferred writing is turned off can be seen by the example of the Promise controller in the tests. This controller does not allow turning deferred writing on unless you install a BBU, and we could not get one in any shop over the last half year. Yes, this controller is greatly handicapped in this test session but we can’t do anything about that.