Hi, I think you have an error in your log­ic. You men­tion that you check that ashift for the pool is set to 12, but ashift is not a pool wide set­ting. That is you can cre­ate a pool with a sin­gle vdev ini­tial­ly and set ashift 12, but you can then add addi­tion­al vde­vs lat­er and they will only have ashift 12 if they are detect­ed to have 4k sec­tors (ie default would be ashift 9).

cheers Andy.