On Sun, Sep 10, 2017 at 12:11:56AM +0200, Gionatan Danti wrote:

Hi all,
I noticed that, when using both LVM thin volumes and ZVOLs, mkfs.xfs
default to using 512-byte sector size.

Would setting sector size to 4K be benefical for filesystem performance?

Probably not. And, worse, you open up the possibility of torn
"single sector" writes if the underlying device isn't a native 4k
sector device.

From what I know, sector size only affect journal and metadata
writes. So, should I manually set sector size to 4K or it is not
worth the (minor) inconvenience?

Only the log might matter for performance, the AG headers are only
read at mount and rarely written because they are so frequently
logged. But, really, the difference between 512 byte and 4k sectors
for the log is going to be pretty damn small. Just use the defaults
and only consider changing them if you observe problems...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com