12 TB hgst HUH721212AL5200 512e sas can it be changed to 4K Sectors?

[mmplpri]

Hi as in the topic is ok to use sg format to change it to logical 4k? From what I read 512e got performance loss because of emulation.( I want to put 6 of them in raid 10)

 

[Chris Moore]

From what I read 512e got performance loss because of emulation.

Wherever you read that must have been a pretty old post.
Have you created a pool with these drives yet?
ZFS is pretty smart and it might automatically pickup that they are 4k drives emulating 512 and set the ashift correctly because this has been going on for quite a while now...

If I recall correctly, you can check this pretty easily with the command zdb -U /data/zfs/zpool.cache | grep ashift

ashift: 9 = 512 sectors
ashift: 12 = 4k

 

[mmplpri]

Hi it setup ashift to 12 but its no difference in performance with 512 vs 4096 logical format?

 

[Chris Moore]

The drive model indicates 512e (which means 512 emulated) and the disk is naively 4k, which FreeNAS (ZFS) detected and formatted it as 4k (ashift 12) so the pool can maximize the capability of the drive. This is as it should be, because ZFS is awesome.

 

[Chris Moore]

PS. You would not normally want to mix 4k and 512 drives in the same pool, but if all your drives are the same, it is not a problem for you.