I think you've got yourself a bit confused.
If you're using snapmirror (volume or qtree) you don't need the lun on the target volume, the initial snapmirror does that for you.
snapmirror also copies the entire lun (typically the whole volume) block for block on the initial set up and then any changed blocks on the schedule you set.
In a DR situ you need to mount that lun on the DR server, and will need to have set up the equivalent igroups etc on the DR filer.