Subject: Storage | August 14, 2015 - 04:44 PM | Allyn Malventano
Tagged: FMS 2015, silicon motion, SM2260, SM2256, SM2246EN, pcie, NVMe, ssd, controller
We’ve reviewed a few Silicon Motion SSDs in the past (Angelbird | Corsair Force LX | Crucial BX100), and I have always been impressed with their advances in SSD controller technology. Their SM2246EN SATA controller was launched two years ago, and strived to be a very efficient and performant unit. Based on our reviews that turned out to be true, and this allowed Silicon Motion to slide into the void left by SandForce, who repeatedly delayed their newer developments and forced the many companies who were sourcing their parts to look elsewhere.
The many SSDs using Silicon Motion’s SM2246EN controller.
Silicon motion pushed this further with their SM2256, which we first saw at the 2014 Flash Memory Summit and later saw driving SLC/TLC hybrid flash at this past Consumer Electronics Show. While the SM2256 makes its way into more and more products, I was glad to see an important addition to their lineup at this year’s FMS:
Finally we see Silicon Motion doing a PCIe controller! This is the SM2260, seen here in the M.2 form factor…
…and here in SATA Express. While the latter will likely not be as popular due to the more limited PCIe lanes present in SATA Express, I’m sure we will see this controller appearing in many PCIe devices very soon. The stated performance figures may be a bit shy of currently comparing SSDs like the Intel SSD 750 and Samsung SM951, but with the recent introduction of Z170 motherboards and RST PCIe RAID, it is now easier to RAID a smaller capacity pair of these devices, increasing the performance of slower units. Further, the point of the SM2260 is likely to get a low cost NVMe PCIe SSD controller into the hands of SSD makers, which can only mean good things for those looking to make the move away from SATA.
I’ve included Silicon Motion’s FMS press blast after the break.
Subject: Storage | August 13, 2015 - 08:12 PM | Allyn Malventano
Tagged: FMS 2015, ssd, sata, SAS, pcie, NVMe, novachips, HLNAND, flash
It turns out Samsung wasn’t the only company to have 16TB SSDs at Flash Memory Summit after all:
Now that I’ve got your attention, Novachips is an SSD company that does not make their own flash, but I would argue that they make other peoples flash better. They source flash memory wafers and dies from other companies, but they package it in a unique way that enables very large numbers of flash dies per controller. This is handy for situations where very large capacities per controller are needed (either physically or logically).
Normally there is a limit to the number of dies that can communicate on a common bus (similar limits apply to DRAM, which is why some motherboards are picky with large numbers of DIMMs installed). Novachips gets around this with an innovative flash packaging method:
The 16-die stack in the above picture would normally just connect out the bottom of the package, but in the Novachips parts, those connections are made to a microcontroller die also present within the package. This part acts as an interface back to the main SSD controller, but it does so over a ring bus architecture.
To clarify, those 800 or 1600 MB/sec figures on the above slide are the transfer rates *per ring*, and Novachips controller is 8-channels, meaning the flash side of the controller can handle massive throughputs. Ring busses are not limited by the same fanout requirements seen on parallel addressed devices, which means there is no practical limit to the number of flash packages connected on a single controller channel, making for some outrageous amounts of flash hanging off of a single controller:
That’s a lot of flash on a single card (and yes, the other side was full as well).
The above pic was taken at last years Flash Memory Summit. Novachips has been making steady progress on controller development as well. Here is a prototype controller seen last year running on an FPGA test system:
…and this year that same controller had been migrated to an ASIC:
It’s interesting to see the physical differences between those two parts. Note that both new and old platforms were connected to the same banks of flash. The newer photo showed two complete systems – one on ONFi flash (IMFT Intel / Micron) and the other on Toggle Mode (Toshiba). This was done to demonstrate that Novachips HLNAND hardware is compatible with both types.
Novachips also had NVMe PCIe hardware up and running at the show.
Novachips was also showing some impressive packaging in their SATA devices:
At the right was a 2TB SATA SSD, and at the left was a 4TB unit. Both were in the 7mm form factor. 4TB is the largest capacity SSD I have seen in that form factor to date.
Novachips also makes an 8TB variant, though the added PCB requires 15mm packaging.
All of this means that it is not always necessary to have huge capacity per die to achieve a huge capacity SSD. Imagine very high capacity flash arrays using this technology, connecting a single controller to a bank of Toshiba’s new QLC archival flash or Samsung’s new 256Gbit VNAND. Then imagine a server full of those PCIe devices. Things certainly seem to be getting big in the world of flash memory, that’s for sure.
Even more Flash Memory Summit posts to follow!
Subject: Storage | August 11, 2015 - 08:40 PM | Allyn Malventano
Tagged: toshiba, ssd, FMS 2015, flash, BiCS, Archive, Archival, 3d
We occasionally throw around the '3-bit MLC' (Multi Level Cell) term in place of 'TLC' (Triple Level Cell) when talking about flash memory. Those terms are interchangeable, but some feel it is misleading as the former still contains the term MLC. At Toshiba's keynote today, they showed us why the former is important:
Photo source: Sam Chen of Custom PC Review
That's right - QLC (Quadruple Level Cell), which is also 4-bit MLC, has been mentioned by Toshiba. As you can see at the right of that slide, storing four bits in a single flash cell means there are *sixteen* very narrow voltage ranges representing the stored data. That is a very hard thing to do, and even harder to do with high performance (programming/writing would take a relatively long time as the circuitry nudges the voltages to such a precise level). This is why Toshiba pitched this flash as a low cost solution for archival purposes. You wouldn't want to use this type of flash in a device that was written constantly, since the channel materials wearing out would have a much more significant effect on endurance. Suiting this flash to be written only a few times would keep it in a 'newer' state that would be effective for solid state data archiving.
The 1x / 0.5x / 6x figures appearing in the slide are meant to compare relative endurance to Toshiba's own planar 15nm flash. The figures suggest that Toshiba's BiCS 3D flash is efficient enough to go to QLC (4-bit) levels and still maintain a higher margin than their current MLC (2-bit) 2D flash.
More to follow as we continue our Flash Memory Summit coverage!
Subject: Storage | August 11, 2015 - 04:59 PM | Allyn Malventano
Tagged: Samsung, vnand, 48-layer, tlc, 16TB, FMS 2015
I get these emails and comments all the time - "I want a larger capacity SSD". Ok, here ya go:
Samsung's earlier 48-layer VNAND announcement was exciting, but we already knew about it going into the keynote. What we did not know was that Samsung was going to blew the doors off of their keynote when they dropped this little gem. It's not just the largest capacity SSD, as this thing is more dense than any HDD's available today as well. That's 16TB of 48-layer TLC VNAND packed into a 2.5" form factor SAS-connected SSD.
...now what do you do once you have such a high density device? Well, you figure out how many you can cram into a 2U chassis of course!
Yup, that's 48 of those new SSDs, making for a capacity of 768TB in a 2U chassis. Samsung described this as a "JBOF" (Just a Bunch Of Flash), so processing the 2 million IOPS this array is capable of will have to be left to the connected system.
No word on pricing, but I'd think we are in 'mortgage the house' territory if you want to put this into your home PC.
There is more to follow from Flash Memory Summit, but for now I've got to run to another meeting!
FMS 2015: *UPDATED* Samsung Adds Layers to its 3D VNAND, Doubling Capacity While Reducing Power Consumption
Subject: Storage | August 11, 2015 - 04:39 PM | Allyn Malventano
Tagged: vnand, tlc, Samsung, FMS 2015, 48-layer, 32GB, 32-layer, 256Gbit
FMS 2015: Samsung Adds Layers to its 3D VNAND, Doubling Capacity While Reducing Power Consumption
Samsung recently added 2TB capacity parts to their 850 EVO SATA SSDs, but today’s announcement may double that. Today at Flash Memory Summit, Samsung has announced a new iteration on their 3D VNAND technology.
Cross section of Samsung 32-layer VNAND. (TechInsights)
The announcement is a new TLC 3D VNAND (the type present in the 850 EVO Series). The new parts consist of an updated die with the following improvements:
- 48 layer VNAND - up from 32 layers of the previous generation
- 256Gbit (32GB) capacity - up from 128Gbit (16GB) capacity of 32-layer VNAND
- 30% reduction in power consumption over 32-layer VNAND
Samsung’s new 48-layer VNAND.
I suspected Samsung would go this route in order to compete with the recent announcements from Intel/Micron and SanDisk. Larger die capacities may not be the best thing for keeping performance high in smaller capacity SSDs (a higher number of smaller capacity dies helps there), but it is definitely a good capability to have since higher capacity per die translates to more efficient flash die production.
The Samsung keynote is at noon today (Pacific), and I will update this piece with any photos relevant to the announcement after that keynote.
I just got out of the Samsung keynote. There were some additional slides with data relevant to this post:
This image simply shows the additional vertical stacking, but adds that Samsung has this new flash in production right now.
The new higher capacity dies enable 1.4x greater density per wafer (realize that this does not mean more dies per wafer, as the image incorrectly suggests).
The power consumption improvements (right) were in the press release, however the speed improvements (left) were not. A 2x improvement in per-die speeds means that Samsung should not see a performance hit if they migrate their existing 128Gbit TLC VNAND SSDs over to these new 256Gbit parts. Speaking of which...
Not only is this new VNAND being produced *this month*, Samsung is retrofitting their 850 EVO line with the new parts. Again, we expect no performance delta but will likely retest these new versions just to double check for any outliers.
There was some more great info from the keynote, but that will appear in another post later today.