Doesn't seem to support 4k out of the box? Some drives - like Intel Optane SSDs allow changing this in firmware (and reformatting) with a manufacturer's utility...

  $ lsblk -t /dev/nvme0n1
  NAME    ALIGNMENT MIN-IO OPT-IO PHY-SEC LOG-SEC ROTA SCHED RQ-SIZE  RA WSAME
  nvme0n1         0    512      0     512     512    0 none     1023 128    0B

  $ sudo nvme id-ns -H /dev/nvme0n1 | grep Size
  LBA Format  0 : Metadata Size: 0   bytes - Data Size: 512 bytes - Relative Performance: 0 Best (in use)

Here is an article about nvme-cli tool :

https://nvmexpress.org/open-source-nvme-management-utility-n...

On Samsung SSD 970 EVO 1TB it seems only 512 bytes LBA are supported:

   # nvme id-ns /dev/nvme0n1 -n 1 -H|grep "^LBA Format"
   LBA Format  0 : Metadata Size: 0   bytes - Data Size: 512 bytes - Relative Performance: 0 Best (in use)

Thanks for checking. SSD review sites never mention this important detail. For some reason the Samsung datacenter SSDs support 4K LBA format, and they are very similar to the retail SSDs which don't seem to. I have the a retail 970 Evo that only provides 512.

I just checked my logs, and none of Samsung's consumer NVMe drives have ever supported sector sizes other than 512B. They seem to view this feature as part of their product segmentation strategy.

Some consumer SSD vendors do enable 4kB LBA support. I've seen it supported on consumer drives from WD, SK hynix and a variety of brands using Phison or SMI SSD controllers (including Kingston, Seagate, Corsair, Sabrent). But I haven't systematically checked to see which brands consistently support it.

At least early WD Black models don't really seem to have 4K LBA support. The format option is listed, but it refuses to actually run the command to reformat the drive to the new "sector" size.

Put your system to sleep and wake it back up. (I use `rtcwake -m mem -s 10`). Power-cycling the drive like this resets whatever security lock the motherboard firmware enables on the drive during the boot process, allowing the drive to accept admin commands like NVMe format and ATA secure erase that would otherwise be rejected. Works on both the WD Black SN700 and SN750 models, doesn't seem to be necessary on the very first (Marvell-based) WD Black or the latest SN850.

I'm pretty sure this is the very first one though — WDS250G2X0C, firmware 101110WD.

I think that's the second-gen WD Black, but the first one that had their in-house SSD controller rather than a third-party controller. The marketing and packaging didn't prominently use a more specific model number to distinguish it from the previous WD Black, but on the drive's label it does say "PC SN700". Also, the first-gen WD Black was 256GB and 512GB capacities, while the later generations are 250/500/1000/2000GB. Firmware version strings for the first-gen WD Black were stuff like "B35200WD", while the SN700/720/730/750 family have versions like "102000WD" and "111110WD". So I would definitely expect your drive to require the sleep-wake cycle before it'll let you reformat to 4k sectors.

You seem to have a lot of info on this topic. Do you run a blog or some other way you disseminate this stuff?

I'm at https://www.anandtech.com/Author/182

But this thread gets into details that are more esoteric than what I cover in most reviews, which are written with a more Windows-oriented audience in mind. Since I do most of my testing on Linux and have an excess of SSDs littering my office, I'm well-equipped to participate in a thread like this.

I highly recommend reddit.com/r/NewMaxx as the clearinghouse for consumer SSD news and Q&A. I'm not aware of a similarly comprehensive forum for enterprise storage, where this thread would probably be a better fit.

Is it genuine 512?

As in, what ashift value do you use with zfs?

Regardless of what sector size you configure the SSD to expose, the drive's flash translation layer still manages logical to physical mappings at a 4kB granularity, the underlying media page size is usually on the order of 16kB, and the erase block size is several MB. So what ashift value you want to use depends very much on what kind of tradeoffs you're okay with in terms of different aspects of performance and write endurance/write amplification. But for most flash-based SSDs, there's no reason to set ashift to anything less than 12 (corresponding to 4kB blocks).

> for most flash-based SSDs, there's no reason to set ashift to anything less than 12 (corresponding to 4kB blocks).

matching the page size?

> the underlying media page size is usually on the order of 16kB

I'd say that's a good reason to set ashift=14 as 2^14=16kb

There are downsides to forcing the OS/FS to always use larger block sizes for IO. You might simply be moving some write amplification out of the SSD and into the filesystem, while losing some performance in the process. Which is why it really depends on your workload, and to some extent on the specific SSD in question. I'm not convinced that ashift=14 is a sensible one size fits all recommendation, even if we're talking only about recent-model consumer-grade NAND SSDs.

FWIW, WD SN850 has similar performance and supports 512 and 4k sectors.