Understanding M.2 RAID NVMe SSD Boot and 2/3x M.2 NVME SSD RAID0 Tested

Samsung’s recent release of their 950 Pro M.2 NVMe SSD (Report here) seems to have caught the industry off guard, much as they do at just about the same time every year. Without question, it is the most powerful SSD in the world for its size, and because of its speed, size and great value mix, has stirred the interest of PC enthusiasts and media professionals who want it now. It is a NVMe SSD, found in a typical M.2 PCIe X4 form factor, and because of this many think that it can be a quick upgrade for their present M.2 SSD with exactly the same look. It’s only when they go to complete that upgrade or build their new system that they learn that M.2 NVMe isn’t quite as plug and play as they might have hoped.

Samsung 950 Pro NVMe M2 512 and 256GB SSDs

The main concern with M.2 NVMe, and specifically the Samsung 950 Pro as it is the only of its kind available at present, is that many are buying this SSD in hopes that it is a quick and easy upgrade for their present M.2 SSD in their ultrabook. On the other end of the spectrum, enthusiasts are running out and buying motherboards with dual M.2 sockets in hopes of creating an amazing bootable RAID0 config with the Samsung 950 Pro, not realizing that the only way to accomplish this is with Intel RST built right into the UEFI/BIOS. Let’s tackle some of these concerns in this report, explain a bit of NVMe compatibility, build a M.2 NVMe RAID configuration and, just for fun, let’s make it bootable!

3 X Samsung NVMe SSDs Boot

PCIE REVISIONS AND LANES

For many, the marketing of M.2 SSDs provided a recognition that storage media would include SATA 3 (up to 550MB/s), PCIe X2 (up to 780MB/s) and then PCIe X4 which hit a realistic ceiling of about 1.4GB/s throughput.  Right around this time, most caught wind of the introduction of PCIe 3.0 which opened up the ‘per lane’ throughput of PCIe devices including M.2 which uses PCIe lanes for data travel.

PCIe Lane Travel

Theoretically, PCIe 2.0 (Gen 2) could reach 500MB/s throughput which meant a PCIe Gen 2 X2 (2 lane) M.2 drive could ‘theoretically’ hit 1GB/s, where X4 (4 lane) could reach 2GB/s, true speeds of course being lower.  The introduction of PCIe Gen 3 increased ‘per lane’ throughput to 984MB/s which brought a M.2 PCIe Gen 3 x4 SSD ‘theoretically’ to just under 4GB/s.  In reality, we have seen 1.4GB/s from a PCIe Gen 2 X4 M.2 SSD and around 2.5GB/s from a PCIe 3.0 x4 SSD, remembering of course that PCIe Gen 3 is still very new.

AHCI AND NVME

The Advanced Host Controller Interface has been around long enough to have fathered, or maybe grandfathered, some of today’s storage experts.  It was first envisioned as the heart and soul of SATA drives. NVMe was introduced to provide much lower latency, as well as higher IOPS and throughput that we see in today’s flash storage.  NVMe also creates a smoother engine with less parts, meaning that error correction and heat is minimized. To the new retail NVMe SSD owner, this translates to faster data transfer in a cooler system.

3 X Samsung NVMe SSDsIn this report, we are running configurations of two and three M.2 NVME SSDs in RAID0 and as the boot drive in our Test Bench. Three M.2’s in RAID…much higher throughput…much higher IOPS…a zero footprint…no heat concerns whatsoever…at 3GB/s read and write speeds with a half million IOPS. Beautiful!

THE NVME UPGRADE

If you are planning on moving your older PC or laptop to the newest Samsung 950 PRO NVMe SSD, let’s slow down just a bit. The new Samsung 950 pro M.2 NVMe is definitely not a simple plug and play upgrade for any other M.2 contained system. NVMe is new and, as such, Windows 10 is the first OS to include driver support. While we understand that NVMe SSDs may ship with an included driver, hardware needs to be considered as well and this is where the Z170 chipset comes in; NVMe has full support and will boot in the right situation. Before our upgrade, we need to ask ourselves if our operating system can support NVMe, if our hardware can support NVMe, and also if our current configuration can support what we intend to buil;d in the case of RAID.

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Karl Ermatinger
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Karl Ermatinger

Les, I am one of those fool hearty individuals who just bought the ASRock motherboard and two of the 950 drives that I want to mirror and use as a database server for my small business. However, my database requires Windows Server 2012 R2. I haven’t even opened up the boxes yet. Do you think I will be able to configure the raid 1 in bios and then install WS 2012 R2 or is that a crazy idea will not work?

Les@TheSSDReview
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When you are in the the UEFI RST, you can select RAID 0, 1 or recovery, along with several stripe levels…..so yes! Great selections…you have a motherboard that supports NVMe, an OS that supports it and two excellent drives! Should be a piece of cake.

Karl Ermatinger
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Karl Ermatinger

Thanks. That’s good news.

But what about adding a 3rd and 4th 950 drive to do raid 10? The 3rd through the m.2 slot but the 4th by adding a m.2 pcie adapter into one of the slots? Do you think that would work?

Les@TheSSDReview
Guest

No. The BIOS is only set up for creating a RAID with the 3 M.2 slots remapped. It also only enables RAID 0 or 1.

Karl Ermatinger
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Karl Ermatinger

Good to know. Thanks.

Karl Ermatinger
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Karl Ermatinger

So, what support or development needs to happen to eventually be able to boot off of any NVMe drive and RAID more drives? Is it enhancement or development of the bios? Is it new technology added to the Intel chipset platforms? New Raid cards?

Les@TheSSDReview
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It would be a BIOS alteration. You could probably go through the OS and create such a RAID but it would not be bootable.

MRFS
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MRFS

(1) 4 or more U.2 ports, replacing motherboard SATA ports
(2) a wider DMI link e.g. x16 lanes for adequate upstream bandwidth
(3) x16 expansion slot(s) wired directly to the CPU
(4) a PLX-type switch to support four NVMe devices on one x16 slot
(5) NVMe RAID controllers with x16 edge connectors
(6) (add your wish list here 🙂

MRFS
Guest
MRFS

p.s. PCIe 4.0 will oscillate at 16 GHz, so a DMI 4.0 link
only increases upstream bandwidth to 8 GB/second.
The DMI link needs to be wider to support upcoming
non-volatile DRAM e.g. Intel Optane, Everspin’s ST-MRAM etc.
x16 PCIe 4.0 lanes @ 2 GB/sec = 32 GB/second.

Nils Sabelström
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Nils Sabelström

if you’re doing this on a server, don’t forget that for every M.2 slot you use on z170, you have to deactivate more sata ports. The sata ports need to use the same PCIe lanes to work. You’ll need to check what gets disabled when using each specific M.2 slot in the manual. In addition to what Les said on that the bios features need to be changed in order to get raid working on more drives, is probably a new chipset, the software-like hardware raid is probably done by the PCH, which on z170 supports a maximum of 3… Read more »

Cape Dave
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Cape Dave

I wish I could slap one of these bad boys in my iMac retina! Darn. Great write up Les.

Les@TheSSDReview
Guest

Have an iMac as well…feel your pain.

HERETIC
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HERETIC

Nice one Les………
Might have been worth while going over the difference between M2 Sata and NVME
again on Page 1 for those that don’t know……………
Wouldn’t mind a $ for everyone who rushes out to buy these and only has M2 Sata slot…haha

Les@TheSSDReview
Guest

Never thought of that…good point.

Patrick Horgan
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Patrick Horgan

It should really be nvme vs ahci, since those are the two communication protocols/interfaces (software). (Hint, nvme has lower overhead and has some increase in throughput and a bigger improvement in latency.) You could also talk about hardware interfaces, i.e. SATA (1,2,3) vs PCIe. (Hint, SATA 3, the current fast version is overwhelmed by the speed of flash drives and limits them. PCIe lets them fly.) You might also mention what Intel said about M.2 being limited for bigger drives because of temperature and available power. Certainly their PCIe drives are noticably faster and available at bigger sizes. Less clear… Read more »

Patrick Horgan
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Patrick Horgan

Of course M.2 can be connected via SATA 3.0 and PCIe. PCIe is a lot faster.

Acer_Predator
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Acer_Predator

Hello guys
I have purchased laptop which has m.2 ssd and it supposed to be connected via pcie x4 but instead it is via ancient ahci..
don’t know why they didn’t put it via pcie
Does that mean , that this nvme works that way I have to split my M.2 SSD and system will put it again together but in RAID ?
My SSD is TOSHIBA THNSNJ128G8NU

Les@TheSSDReview
Guest

Your SSD will work in there as it is a SATA 3 SSD. With respect to the connection, it is still most likely PCIe x4 which means it can house a much faster Samsung XP941 pr Samsung SM951 (both AHCI) but it most likely wont yet be able to work with the 950 pro as it is NVMe…

Acer_Predator
Guest
Acer_Predator

aah so it is not working because mine m.2 Toshiba does not support NVMe right ?
Only Samsung 950 supports NVMe ?
EDIT : just found ; The Samsung MZVPV supports NVMe
OK thanx

dravo1
Guest
dravo1

The 950s are really beginning to make their presence known. The prices on the Intel 750s are dropping substantially.

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