12 Gb/s SAS: An Impressive Demonstration Of Speed
When we saw our first 12 Gb/s SAS demo, the enthusiasts in us naturally got excited. Future-looking technology always seems to do that. But a lot changed around us since we sat in on those exhibitions. We now have entry-level client SSDs reading and writing 500 MB/s. Prices on solid-state storage continue falling, both for desktop power users and IT professionals. Really, only the drive interfaces remained constant.
The lack of change in that particular area is going to, well, change. Between SATA Express, SCSI Express, NVMe, SoP, and SFF-8639, everything from physical interfaces to protocols and connectors will be different. Through all of that, though, SAS will persist. A 12 Gb/s interface should give the standard plenty of room to scale, even as multiple PCIe-based protocols fight for acceptance.
LSI is going to help push the adoption of 12 Gb/s SAS with the introduction of its SAS 9300-8e. We don't yet know how much more it's going to cost, but we have to imagine there will be a premium beyond what you pay for today's 6 Gb/s HBAs. Then again, compared to the number of ports it'd take to match the performance of eight 12 Gb/s interfaces, we see plenty of room for next-gen SAS to become a value play, too. If that turns out to be true, there's very little reason not to take the plunge when you're in the market for your next HBA. Future-proofing is just smart, even if there aren't more 12 Gb/s-capable drives and backplanes just yet.
On our bench, the SAS 9300-8e performed well in both 6 and 12 Gb/s modes. It certainly doesn't seem to be bottlenecking the one 12 Gb/s SSD to which we have access, and it's nearly as fast as Intel's native SATA controller when we attach the company's SSD DC S3700, too.
But LSI's controller is an enabler. Really, the star of this show turns out to be HGST's SSD800MM. Sequential reads topped 150,000 IOPS and 1 GB/s. Naturally, it blew past every 2.5" SSD we've ever reviewed, enterprise and client alike. Its performance, in many cases, comes closer to the PCI Express-based cards we've tested. Although write performance didn't come close to the read numbers, it still landed 30 to 50% higher than the fastest 6 Gb/s SSDs. Much of that comes from a 12-channel controller co-developed by Intel and tons of over-provisioning. When you combine those variables and add in high-endurance MLC NAND, you end up with a product that excels in almost every category that a good enterprise-oriented product needs to cover.
We were particularly impressed with the performance of the SSD800MM at 6 Gb/s. Normally, when you have a big technology breakthrough, the first prototype products aren't very well-optimized. The fact that the SSD800MM does so well at a lower interface transfer rate makes it an intriguing offering, even in businesses that don't have 12 Gb/s SAS equipment yet. Of course, price plays a bit part in our interest. As of now, HGST isn't willing to comment, so we can't give this drive a blessing just yet.
Hopefully, both of these products are indicative of what we'll see 12 Gb/s SAS do in the next few years. Right out of the gate, we're off to a pretty fantastic start.
