A networked data storage system includes data movement logic and a virtual machine for executing a data management processing plan which is generated by a facility outside the storage array based on statistical information associated with extent level activity metrics provided by the storage array. Dynamically updated and automatically generated data management processing plans are provided to the storage array in the form of units of compiled byte code which the storage array is able to verify and execute using a virtual machine. The virtual machine interfaces with the environment in which it is embedded in a carefully constrained manner, thereby preventing clearly undesirable operations.