Using the *real* sector/block size of a mass storage device for ZFS

[Dustin Wenz]

We have been upgrading systems from FreeBSD 9.2 to 10.0-RELEASE, and I'm noticing that all of my zpools now show this status: "One or more devices are configured to use a non-native block size. Expect reduced performance." Specifically, each disk reports: "block size: 512B configured, 4096B native".

I've checked these disks with diskinfo and smartctl, and they report a sector size of 512B. I understand that modern disks often use larger sectors due to addressing limits, but I'm unsure how ZFS can disagree with these other tools.

In any case, it looks like I will need to rebuild every zpool. There are many thousands of disks involved and the process will take months (if not years). How can I be I sure that this is done correctly this time? Will ZFS automatically choose the correct block size, assuming that it's really capable of this?

In the meantime, how can I turn off that warning message on all of my disks? "zpool status -x" is almost worthless due to the extreme number of errors reported.

	- .Dustin