1. A method of placing workloads in a multi-array system comprising a plurality of storage arrays, the method comprising: determining, for each of a plurality of storage arrays, a current system activity level trend of the storage array, the current system activity level trend including a plurality of performance metrics of the storage array; receiving a performance profile of a workload to be executed on one of the storage arrays; generating, for each of the plurality of storage arrays in dependence upon the current system activity level trend of the storage array and the performance profile of the workload, a projected system activity level trend for the storage array, wherein the projected system activity level trend identifies an expected impact to the performance metrics of the storage array created by placing the workload on the storage array; identifying, in dependence upon the projected system activity level trend for each of the plurality of storage arrays, an optimal storage array for receiving the workload; and placing the workload on the optimal storage array.