You need to start the reallocation manually and when you do an AGGR reallocate, volumes inside the aggregate will be processed as well..
After reallocation is enabled on your storage system, you define a reallocation scan for the aggregate on which you want to perform a reallocation scan.
reallocate start -A [-o] [-i interval] <aggr_name>
--> Because blocks in an aggregate Snapshot copy will not be reallocated, consider deleting aggregate Snapshot copies before performing aggregate reallocation to allow the reallocation to perform better.
--> Volumes in an aggregate on which aggregate reallocation has started but has not successfully completed will have the active_redirect status. Read performance of such volumes may be degraded until aggregate reallocation has successfully completed. Volumes in an aggregate that has previously undergone aggregate reallocation have the redirect status