Upgrading to 4k disks

[hibble]

I am in the process of replacing some old hard drives with larger 4k based ones.

Will ZFS auto use 4K sectors on the new drives as they resilver or am i better off bilding a new pool from scratch with the force 4k option?

 

[cyberjock]

Nope, you'll be using whatever the zpool uses. If you want to use 4k sector disk on a zpool that didn't have 4k sector checked before your best bet is to make a new zpool. There is no way to fix this, but there has been discussion about this and new pools may default to 4k because there isn't a significant penalty if you use 4k in 512-byte sectors.