[OpenIndiana-discuss] moving existing rpool onto larger disks, in-place: zpool/zfs ashift/blocksize musings

[Hans J. Albertsson]

I have an OI151a4 system with old 500GB disks in a mirrored pair for the 
rpool, and no further disks.
For various reasons I'd like to expand the available space by replacing 
the 500GB disks with 2TB disks.
I'd like to do this IN-PLACE, but I see a few problems in that the new 
disks are naturally 4K blocksize, but falsely report 512 byte blocksize.

First: Can you ever efficiently migrate a zpool with ashift=9 to a 4k 
block disk by just adding the new disk as a 3rd mirror? Regardless of 
what blocksize the disk reports?

Second: Can you manage the problem of the false blocksize report in a 
situation like this?

Third: How can one check to see  what parameters (like ashift( a 
particular pool uses?