When SyncMirror is enabled, the reserved space of aggregate snapmirror space should be set.
aggr create {aggr_name} {number_of_disks}
# Create an aggreate with normal settings
aggr mirror {aggr_name}
# Make the aggregate mirrored
aggr status {aggr_name} -r
# Verify the disk assignment. As descriped in the documents, an mirrored aggregate should seperate the two plexes into different disk pools.
aggr split {plex_name} {new_aggr_name}
# Split the mirrored aggregate into two seperate aggregate