Starting in mongosync-beta 1.8, sets a migration name for a sync
operation. For example, you can set a migration name to identify each
sync operation from multiple source clusters into one destination
cluster.
The migrationName string can contain up to 44 alphanumeric
and underscore characters. migrationName is appended to the string
"mongosync_internal_" to set the migration metadata database name.
If you set migrationName to
"cluster_27000_to_cluster_35000_sync", the resulting mongosync
metadata database name is
"mongosync_internal_cluster_27000_to_cluster_35000_sync".
For a complete example, see :ref:`c2c-quickstart-many-with-one`.