1. A system, at least partly implemented in hardware, for performing data storage operations that transfer data from a source to a destination in a hierarchical storage system, the system comprising: a global manager server in the hierarchical storage system coupled to two or more storage managers, each of which is subordinate to the global manager server, wherein the global manager server comprises at least one processor, wherein the two or more storage managers control multiple data storage operations in their respective storage operation cells and communicate information related to the data storage operations of their respective storage operation cells to the global manager server; wherein each of the two or more storage managers controls data storage operations in their respective storage operation cells in accordance with an applicable filter or rule received from the global manager server, and wherein each of the two or more storage managers controls one or more media agents that are configured to migrate a primary copy of data produced at a client computer in the respective storage operation cell to a destination location in order to create a secondary copy of the data in a secondary storage during a data storage operation, wherein each of the two or more storage managers tracks and stores information associated with where the secondary copy is stored in the secondary storage; wherein the global manager server: receives reports related to performance of the multiple data storage operations in the storage operation cells; performs a quantitative comparison of performances of different data storage operations controlled by the two or more storage managers; determines the filter or rule, wherein the filter or rule modifies active conveyance of data from client computers to destination locations during data storage operations based in part on the determined filter or rule; determines a set of all storage operation cells in the system to which to apply the filter or rule; and applies or provide the filter or rule to the set of all storage operation cells; wherein the filter or rule includes transferring a waiting storage operation from a given cell to another cell when the global manager server determines that the waiting storage operation will not complete within a given time.