Post your 4Kn (4K Native Advanced Format) experiences here

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Terry Kennedy

Well-Known Member
Jun 25, 2015
New York City

This is a thread to discuss real-world experiences with 4Kn disk configurations. 4Kn drives expose the underlying 4KB sector size to the operating system, as opposed to 512e which hides the 4K sectors (with varying degrees of success) from the operating system.

There is a dearth of real-world documentation with 4Kn drives. Most of the information available discusses "4K sectors" without going into any detail about the drive being 512e or 4Kn.

Please use the following format as a guideline when replying:

Drive brand / model / firmware version:
Interface type (SAS/SATA):
Controller brand / model / firmware version:
Operating system name / version:
Filesystem type:
Bootable (yes / no / untested):
Any other comments:

Terry Kennedy

Well-Known Member
Jun 25, 2015
New York City
Drive brand / model / firmware version: HGST HUH728080AL4200 A515 (He8 family)
Interface type (SAS/SATA): SAS
Controller brand / model / firmware version: LSI 9201-16i
Operating system name / version: FreeBSD 10.3
Filesystem type: ZFS
Bootable (yes / no / untested): Untested
Any other comments: Running an 85TB ZFS pool (16 * 8TB drives) on a Supermicro X8DTH-iF motherboard. I did not test booting as I think booting a 4Kn drive requires a UEFI BIOS, which the X8DTH-iF does not have.

Terry Kennedy

Well-Known Member
Jun 25, 2015
New York City
What's the point of this 4kn format? Is it suppose to handle 4k video files better?
Nothing to do with video. Just about all current production hard drives use 4KB sectors internally. The first of those drives provided an emulated 512 byte sector size, since no operating systems / controllers knew what to do with 4KB sectors. This means that for an isolated write of a single 512 byte sector, the drive has to read one of its 4KB sectors, replace the appropriate 512 byte segment with the new data, then write that sector back to disk. This can seriously penalize performance, particularly in the case where the operating system wants to write 4KB of data, but not aligned with the underlying 4KB sectors on the drive.

Native 4KB means that the drive only works on 4KB blocks and doesn't emulate traditional 512 byte sectors. Since most operating systems allocate data in 4Kb or larger chunks, that means neither side has to pretend to want 512 byte sectors.


Well-Known Member
Mar 18, 2016
What's the point of this 4kn format?
- Future proofing (larger drive sizes by using bigger blocks and 64bit addressing)
- Efficiency (less overhead for checksums/ecc)
- (To some degree better "performance")

Yarik Dot

Active Member
Apr 13, 2015
We have 2 use cases:

We use them in our linux based storage - roughly 100 pieces, without any issue

On virtualization host:
There was no support of vmware at the time of installation, so we were forced to use hyper-v on 4kn drives. The situation might be different these days.


Feb 27, 2018
Los Angeles
Very interesting. Yes when I go to the Seagate website I see there are different kinds of HDDs, one is the 512e and the other is 4k block size. So those 4k drives would work in standard windows server 2016 environment? I'd just be using them to store meida files, like video files on them.

Also, to throw in a wrench in my mind. I've been playing around with highpoint NVMe raid controller cards which has a software raid. I can actually change the sector size from 512 to 4k using the raid software. But I don't know if the Samsung Evo 970's support 4k sector size. Or is it block size, it get confused with the terminology.


Well-Known Member
Jan 6, 2016
Yep can confirm your windows 2016 has no issues at all with 4Kn.
ESX no way.


Dec 24, 2016
4x Seagate 4Kn 4TB 12gbs SAS drives, LSI9300-4i HBA passed through to a 2vcpu, 32GB NAS4free VM under ESXi 6.5, on a 6core, 48GB, 128GB SSD Dell R420. The NAS records 11 cams 24/7 and backs up 2 other NAS’s. Trouble free except Nas4free Hoover’s the whole 32GB into alarm.