Western Digital's Red series of drives for network-attached storage systems has a significant share in various NAS market segments. The series started off with a focus on hard drives, and more recently WD Red SSDs were introduced in Q4 2019, a few years after the SanDisk acquisition. These SATA SSDs (in both 2.5" and M.2 form-factors) were based on Marvell 88SS1074 controllers and targeted caching applications.

The increasing popularity of tiered storage, coupled with the deployment of NVMe (in the form of add-in cards, and now, natively in NAS boards) has prompted Western Digital to create a new member in the WD Red family. The new WD Red SN700 comes in 5 capacities ranging from 250GB to 4TB.

WD Red SN700 NVMe SSDs for NAS
Capacity 250 GB 500 GB 1 TB 2 TB 4 TB
Model Number WDS250G1R0C WDS500G1R0C WDS100T1R0C WDS200T1R0C WDS400T1R0C
Controller SanDisk In-House?
M.2-2280, PCIe 3.0 x4, NVMe 1.3
(22.15mm x 80.15mm x 2.38mm)
(22.15mm x 80.15mm x 3.58mm)
Seq. Read Max
(128KB @ QD32)
3100 MBps 3430 MBps 3400 MBps
Seq. Write Max
(128KB @ QD32)
1600 MBps 2600 MBps 3000 MBps 2900 MBps 3100 MBps
Rand. Read IOPS
(4KB @ QD32)
220K 420K 515K 480K 550K
Rand. Write IOPS
(4KB @ QD32)
180K 380K 560K 540K 520K
SLC Caching Yes
DRAM Buffer ? ? ? ? ?
Opal Encryption No
Power Peak 9.24 W
PS3 (LP) 70 mW 100 mW
PS4 (Sleep) 3.5 mW 5 mW
Warranty 5 years
MTBF 1.75 million hours
TBW 500 1000 2000 2500 5100
DWPD 1 0.7
Addl. Info. Link
MSRP $65 $80 $145 $290 $650

A PCIe 3.0 x4 NVMe drive can provide a quantum leap in I/O performance, especially over pure HDD-based systems. NAS units are fast becoming hyperconverged application servers, and NVMe drives can improve user experience with both storage tasks as well as application tasks. In particular, tasks related to workloads like virtualization, multi-user collaborative editing and other similar applications. The benefits for traditional enterprise workloads such as intensive databases are also evident, even when the NVMe drive is used purely as a caching drive. Interestingly, the 1TB and lower capacity models have a 1 DWPD rating, while the 2TB and 4TB ones have a 0.7 DWPD endurance number.

It must be noted that Seagate has already released two generations of NVMe drives for the NAS market in their IronWolf series. WD is playing a bit of a catch-up in this particular market segment, but its SanDisk heritage and vertical integration can possibly give the WD Red SN700 an edge over the IronWolf series.

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  • bug77 - Tuesday, September 28, 2021 - link

    I'm guessing still pricey.
    Too bad there are no NAS enclosures designed for NVMe only. Even a 2-bay standard enclosure is a pretty bulky thing to have on your desk.
  • at_clucks - Tuesday, September 28, 2021 - link

    Also I'm sure WD managed to somehow make these SSDs SMR.
  • at_clucks - Tuesday, September 28, 2021 - link

    P.S. A NVMe only NAS may exist at some point but it doesn't make that much financial sense right now. If it is to have any reasonable capacity it will need quite a few slots (a lot of available PCIe lanes), quite a bit of processing power, and necessarily has to be faster than 10G (so probably 40G) otherwise it makes no sense. This would make it expensive even before filling it with drives compared to the equivalent HDD+SSD cache NAS. And you'd lose features like hot swap.

    So manufacturers probably don't see more than a very niche market for a very expensive device. If you have 10+G network around you probably don't want *just* NVMe, you'll want and SSD cached HDD NAS for capacity *and* speed.
  • sandtitz - Tuesday, September 28, 2021 - link

    NVMe NAS systems are available, Dell Powermax for example.
    NVMe drives are hotswappable, though obviously not in your home pc.

    In a 10G or slower network even a SATA or SAS based NAS can easily saturate the network.
  • Kjella - Friday, October 1, 2021 - link

    For streaming/file copy maybe. Even a small amount of random IO on top makes those pretty numbers go away real fast. I'd love to go all SSD if it wasn't for the cost, even on a 1Gbit NAS.
  • lightningz71 - Thursday, September 30, 2021 - link

    I would imagine that there is a space in the market for a M.2 SATA based NAS. For roughly the footprint of a portable, external optical drive, you could easily fit 6-8 m.2 SATA SSDs in it, with a small SATA controller, a tiny ARM processor to handle the light weight OS, a gigabit port, a USB-C port and an external power brick (if PoE or USB-C power isn't available). It would have more than enough throughput available to saturate even a 2.5Gbps link and draw very little power.

    There's no need in the pro-sumer market space for a multiple NVME drive NAS box, and higher performance solutions already exist in the professional market.

    Does the above solution work? I already have a recycled old SFF PC with a quad port M.2 SATA card in it with 4 M.2 SATA SSDs and two more SATA SSDs in the drive bays running a linux NAS distribution. I got the drives as used pulls from business laptops that were being retired. It does just fine for what I need. I have a big external USB connected HDD for online backups that I swap with another one monthly so I can have an off line backup that's not too old.
  • Valantar - Wednesday, September 29, 2021 - link

    It needs saying: isn't one of the main advantages of a NAS to _not_ have it on your desk?
  • NextGen_Gamer - Tuesday, September 28, 2021 - link

    Small typo in the table: last one should be 4TB, not 4GB. Hopefully you guys get confirmation on the controller soon. If WD is just using some off-the-shelf one from Marvel or Phison, then we pretty much already know how the drive will perform. But if it using an in-house developed controller, that makes it much more exciting, even more so if it happens to be a brand-new purpose-built controller for this drive.
  • PaulHoule - Tuesday, September 28, 2021 - link

    Pro Tip. Thousands of SKUs for different applications is the hardware equivalent of auto-tune in music.

    Give Best Buy thousands of SKUs to stock and they won't stock any of them. It really makes no sense at all in 2021 with shortages. Vendors should focus on a small number of SKUs that are high quality and reasonably priced. Give people too many choices and they'll just use cloud storage.
  • Drkrieger01 - Tuesday, September 28, 2021 - link

    Any word on if the controller handles sync transfers well? Just wondering if this is set up more like an enterprise drive versus consumer, and I'm also guessing it doesn't have power loss protection?

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