I don't think the newly arriving data will try to go to the migration
target is migration is in progress.  My experience shows the data arriving
in the disk pool while the migration is going on.  When migration starts,
ADSM determines what data to migrate based on the client with the most data
in that pool and then migrates all that client's data.  If the low
migration threshold is hit, migration stops, else the next largest client's
data is migrated and the loop repeats.

Kelly