Which 6 Gb/s SAS Controller Is Best?
Overall, the four SAS-based RAID controllers we tested demonstrate good performance. None of them lack important features, and they're all usable in entry-level and mid-range servers. Aside from their performance characteristics, they stand apart by offering handy features like mixed-environment SAS and SATA support, along with scalability via SAS expanders. The SAS 2.0 standard, which all four controllers support, not only bumps bandwidth up from 3 Gb/s to 6 Gb/s per port, but also introduces new features like SAS zoning, allowing multiple controllers to access storage resources behind a single SAS expander.
In spite of similarities like low-profile form factors, eight-lane PCI Express interfaces, and an octet of SAS 2.0 ports, each controller has distinct strengths and weaknesses, from which derived recommendations for ideal use cases.
Overall, LSI's MegaRAID 9265-8i is the fastest controller, especially in with regard to I/O throughput. While it does have some weak spots, like not-so-stellar RAID 5 and 6 performance, the MegaRAID 9265-8i wins most benchmarks and presents itself as a well-rounded, professional-grade solution. Its $630 street price is also the highest in this round-up though, so you have to keep that in mind. But for that price you get a future-proof controller that runs rings around its competition, especially mated to SSDs. It clearly has performance in reserve, which could come in handy when more storage is added down the road. Moreover, you can enhance the performance of LSI's MegaRAID 9265-8i by adding the FastPath or CacheCade upgrades, so long as you're willing to pay extra for them.
The Adaptec RAID 6805 and Areca ARC-1880i controllers offer similar performance at similar mid-range price points ($460 versus $540 street price). Both are good performers as far as data throughput goes, in addition to I/O. The Adaptec controller ekes out a small performance advantage over the Areca controller, and it also offers the desirable Zero Maintenance Cache Protection (ZMCP) feature, replacing conventional battery backup units and the service that goes into keeping them running with a bit of NAND flash and a capacitor.
HighPoint's RocketRAID 2720SGL sells for about $170, which is the bargain bin compared to the three other controllers reviewed today. Its performance is acceptable if you're using it with conventional disk drives, though clearly a step down from what Adaptec or Areca give you. Don't use this one with SSDs.
I had a hard time deciding between 9265-8i, 1880 and 6805 a month ago. I bought the 6805 and always wondered why RAID-10 was not as fast as I thought it should be. This reviewed proved my worries.
I eventually went to RAID 6 with 6 Constellation ES 1TB disks. Here's where the adaptec really shines. This is for a photo/video storage/editing disk array.
Admittedly if I have a choice again I would have picked the Areca after seeing the numbers. Adaptec was the cheapest among all of them so it's not too much of a regret.
That said can you please talk more to the differences performance wise between SATA and SAS? I understand the reliability argument, however I wonder if for my purposes I would not be better served by using cheaper SATA disks over SAS disks?
I would also love some direction with regard to a good enclosures/power supplies for a hard drive only enclosure. I realize I am quickly priced out of an enterprise solution in this arena, but have seen at least a couple cheaper options online such as the Sans Digital TR8M+B. (This enclosure is normally bundeled with some RocketRaid controller which I would probably discard in favor of either the Adaptec or LSI solution.)