We are running 8.3.1 cDOT and just added disks to an aggregate. In the 7-mode days we would need to run an aggr -reallocate. I am not able to find a command to complete a reallocate in cDOT. I was able to find a -free-space-reallocation option, but its not a 1 time run and appears to have possible performance implications.
I was not able to find any documentation on best practices after adding disks to an aggr.