A recommendations manager (RM) of a file system service identifies a file system object group (FSOG) for which proactive placement recommendations are to be generated using statistical analyses. Usage metrics collected from the FSOG are used to train a model. Predictions obtained from the model are used to generate a recommendation to transfer a file system object proactively from one storage device group of the service to another. The recommendations are provided to an object migrator of the service to initiate the transfer.