Slashdot Mirror
Start-up Claims SSD Achieves 180,000 IOPS
Lucas123 writes "Three-year-old start-up Pliant Technology today announced the general availability of a new class of enterprise SAS solid state disk drives that it claims without using any cache can achieve up to 180,000 IOPS for sustained read/write rates of 500MB/sec and 320MB/sec, respectively. The company also claims an unlimited number of daily writes to its new flash drives, guaranteeing 5 years of service with no slowdown. 'Pliant's SSD controller architecture is not vastly different from those of other high-end SSD manufacturers. It has twelve independent I/O channels to interleaved single level cell (SLC) NAND flash chips from Samsung Corp. The drives are configured as RAID 0 for increased performance.'"
They're fishing for a price point? Quick, everybody make a comment to the effect that such a drive is only worth about $10...
Orwell: "In a Time of Universal Deceit, telling the Truth is a Revolutionary Act"
Start-up Claims SSD Achieves 180,000 IOPS
Claims? As in no one else but the company has stated this "fact"? I wish this article waited for a review before being posted :S
Disclaimer: I am not god.
We may not be created equal
But we can be treated equal.
I used pre-production versions of these. I tested them with Terabytes of test data in random write tests. They are amazing, and can saturate a 1Gb FC connection with random writes. They are very resilient. We put these in my company's demo boxes to show that our architecture can compete with EMC. Kind of cheating, but we told them that it was a special drive that enables us to show the limits of our storage management architecture in a small, 1U box, instead of just showing you the limits of physical hard drives.
We beat their 8Us of EMC hard drives by 34% with just one of these 2.5" drives, and we had bottlenecks all over the place in our small demo box. And they did the testing, not us.
The thing about these drives is that they are more expensive ($/GB) even than registered ECC DDR2/3 RAM, which obviously is going to be even faster.
Only worth about 10$? You're crazy, I'd pay up to 20$ for such a drive!
With all the fast SSD's I've tested I've found the controllers to be a bigger bottleneck than the SSD itself. I've seen 50% performance gains on the Intel x-25e's simply by hooking them to a second machine with a different controller. Even with the best performer (Intel ICH9) I still had the feeling that the controller might have been holding the drive back a bit. Haven't tried it with an ICH10 based board yet though so perhaps there's significant improvements there. (on further reading they claim to be using SAS, I'm not aware of any really high performance SAS chipsets, they all seem to be targeted at RAID's of traditional HDD's and so can't keep up with SSD, I'd really be interested in some details of their test).
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Yeah, but a head crash on a hard drive kills the entire drive, same with a motor failure or most hard drive failures, even though there are multiple heads and platters. Think of channels in a SSD as platters in a hard drive, not separate hard drive-lets.
With a solid state drive, with block recovery algorithms, no moving parts, etc, it's less of a risk. There's still a risk of course, but it's less ridiculous. Anyway, internal RAID 0, RAID 5, RAID 10, all killed totally by a total device failure.
Well, I don't know the whole setup, just that it was about 10 drives (15k) SCSI (not SAS) in a RAID 5. I don't know how much cache. It was a Clarion unit. But, the customer thinks, "Wow, your little box that I've never heard of has just beaten EMC." They don't get into the technical details when they make that sort of decision.
The 12 independent channels can be accessed as RAID-0 if needed, giving upwards of 12x the speed of a single channel, but this is done by the onboard controller, not by anything else.
Intel uses 10 independent channels to achieve their speeds, also in a "RAID-0" like setup.
That doesn't get around the bottleneck at all.
I get nearly 2X the speed of a single drive that is limited by SATA. Theoretically, that might not be the same thing but for all *PRACTICAL* purposes, it gets around the bottleneck just fine for me :-)
Emphasis on "in theroy" as I had an SSD go with absolutely no warning less than 48 hours after installation, but I'm filing that under bad luck.
I'd call that good luck. Bad luck would be 48 days.
Due to the 8/10 encoding on SATA, SAS, and a few other serial technologies, it's really easy to convert between megabits/gigabits of total bandwidth and megabits/gigabits of encoded bandwidth. For SATA/SAS 3Gib/s, it's 300MiB/s. For 6Gib/s, it's 600MiB/s.
They didn't say "unlimited writes forever" they said "unlimited writes for 5 years", and that's obviously limited to what the drive can do, i.e. 180,000 operations per second for their 3½ inch drive.
At 180,000 IOPS * 5 years you're looking at 28,401,233,400,000 write operations.
At 320 MB/s * 5 years you're looking at writing 47 petabytes worth of data.
Now, obviously none of those figures are realistic, as there is no way you would be writing 100% and never ever reading your data again. But they are claiming that their drives can handle those loads without failing. In order for their device to handle that many writes, they'll need a minimum of 284,012,334 cells. That's assuming 1 bit/write of course. The more realistic thought is 4 kB/operation. Now you're looking at 9,306,516,160,512 cells or 136 GB, and I think it's safe to assume that their 3½ inch drive will store more than 136 GB of data.
It's not unlimited forever, it's unlimited within a timespan and capabilities of the device. And just doing the math makes this seem entirely plausible.