A Sexy Storage Spree: The 3 GB/s Project, Revisted

Conclusion: Second-Generation 6 Gb/s Systems Needed

An armada of 16 SSDs combined in a fast (albeit risky) RAID 0 arrangement would probably not be something many users would set up in reality, neither in the corporate world nor in general use. Then again, it was not our goal to create a realistic test scenario, but to find out just how much power we could tease out of a bunch of decent flash SSD drives a year after our first attempt at doing the same thing.

So, here's what we found: the rebirth of our extreme RAID, this time comprised of MLC-based Samsung 470 SSDs instead of more expensive SLC-based Intel X25-Es, generates throughput of more than 3 GB/s and I/O performance at up to 170 000 operations per second. However, the high read/write speeds are not as constant as we expected. Just like the I/O performance levels, they unfold with increasing queue depth, reading their peak values beyond 3 GB/s only in sequential measurements.

We expected the LSI MegaRAID 9260-8i and MegaRAID 9280-24i4e RAID controllers to perform admirably, which they did. But we did not expect them to quietly bottleneck our performance ambitions so severely. The manufacturer claims each controller can manage a maximum of 150 000 IOPS and around 1600 MB/s, which seems like quite a lot. This is actually true for most conventional setups, so long as you don’t go for extreme performance like we are here. Mathematically, 16 SSDs at up to 261 MB/s each could jump over the 4 GB/s line, which is impossible with current hardware. We want to make clear that this isn’t an issue of 3 Gb/s signaling versus 6 Gb/s, but rather a matter of bandwidth and I/O capabilities on the host system side, and, more important, the RAID controller. It all goes to show how important balance is in your own high-end storage. It's not hard to conceive of a similar bottleneck affecting daisy-chained JBODs.

The RAID story is certainly far from over. For one thing, the next generation of SAS-capable RAID controllers will provide much higher bandwidth and I/O capabilities. New products, such as LSI’s recently-announced 9285-8e/i, which we’ll be looking at soon, come with 6 Gb/s interfaces. At the same time, the latest 6 Gb/s SSDs demonstrate impressive throughput, which shows that there still is a lot of room to grow performance. Expect a new extreme RAID SSD project to follow up later this year.

  • jeff77789
    I want one of those...
  • user 18
    jeff77789I want one of those...
    Why stop at one? I want two!
  • burnley14
    Wow, throughput in GB/s. Makes my paltry single SSD look shameful. How fast did Windows boot up out of curiosity?
  • the associate
    Overkill benches like this are awesome, I can't wait to see the crazy shit were gona have in 10 years from now.

    burnley14How fast did Windows boot up out of curiosity?
    I'd also like to know =D
  • abhinav_mall
    How many organs I will have to sell to get such a setup?
    My 3 year old Vista takes 40 painful seconds to boot.
  • knowom
    You can use super cache/super volume on SSD's or even USB thumb drives to dramatically improve the I/O and bandwidth at the expense of using up a bit of your system ram still the results are impressive and works on HD's as well, but they suffer from access times no matter what.

    I don't even think I'd bother getting a SSD anymore after using super volume on a USB thumb drive and SSD the results are nearly identical regardless of which is used and thumb drives are portable and cheaper for the density you get for some messed up reason.
  • knowom
    I'd be really interested to see super cache/super volume used on this raid array actually it can probably boost it further or should be able to in theory.
  • x3style
    abhinav_mallHow many organs I will have to sell to get such a setup?My 3 year old Vista takes 40 painful seconds to boot.Wow people still use vista? Was that even an OS? It felt like some beta test thing.
  • nitrium
    I suspect you'll all be VERY disappointed at how long Windows takes to boot (but I'd also like to know). Unfortunately, most operations in Windows (such as loading apps, games, booting, etc) occur at QD 1 (average is about QD 1.04, QD > 4 are rare). As you can see on Page 7, at QD1 it only gets about 19 MB/sec - the SAME speed as basically any decent single SSD manufactured in the last 3 years.
  • kkiddu
    mayankleoboy1holy shit! thats fast. how about giving them as a contest prize?
    I WANT 16 OF THOSE !

    For God's sake, that's $7000 worth of hardware, not including the PC. DAMN DAMN DAMN !! 3 gigabytes per second. And to think, that while on dial-up 4 years back, I downloaded at 3 kilobytes per second (Actually it was more like 2.5 KB/s).