1. A system to optimize data placement for a multi-tiered storage system comprising: a data collector configured to collect system configuration data and system performance data; a plurality of data placement optimizers each configures to analyze the system configuration data and the system performance data for developing a corresponding data movement plan for execution; a data placement arbitrator configured to arbitrate potential conflicts between at least two of the data movement plans slated to access the same data in the multi-tiered storage system to form an execution plan, wherein arbitration of the potential conflicts is performed prior to execution of the data movement plans and all of the data movement plans generated by the plurality of data placement optimizers are included in the execution plan or removed as a result of the arbitration; and a data mover configured to, after receiving the execution plan from the data placement arbitrator, perform the data movement plans according to the execution plan, wherein: the data mover is further configured to maintain a plurality of priority queues, each priority queue has a different priority; each data migration plan has a priority and is entered into a priority queue having a corresponding priority; and the data mover is further configured to execute the data migration plans in a higher priority queue more frequently than the data migration plans in a lower priority queue.