One method includes receiving partitions, generating assignment plans for assignment of the partitions to servers based on dimensional values of dimensions as determined by different assignment heuristics, selecting one of the assignment plans for execution based on analyzing the dimensional values in accordance with the assignment plans, and executing the selected assignment plan on scalable storage. Another method includes determining, for a triggered optimization module that a server is over utilized on a dimension, selecting candidate operations for partitions assigned to the server, for a higher priority optimization module than the triggered optimization module, removing a candidate operation from the candidate operations that would diminish a modeled state of scalable storage, determining an operation of the candidate operations that would improve the modeled state of the scalable storage with respect to a metric of the dimension on the server, and executing the operation on the scalable storage.