1. A method of managing distributed storage resources including at least a first storage unit and a second storage unit, comprising: while the first storage unit and the second storage unit are online, monitoring workloads associated with objects stored in the first storage unit and the second storage unit at multiple points in time over a time interval, and monitoring performance of the first storage unit and the second storage unit, each of the monitored workloads being a function of time-correlated samples of measured data including the number of outstanding input output requests to an associated object and an average size of input output requests to the associated object; computing normalized load metrics for the first storage unit based on time-correlated sums of the workloads monitored on the first storage unit over the time interval, each of the workloads monitored on the first storage unit over the time interval being associated with a respective one of the objects stored in the first storage unit, and the monitored performance of the first storage unit, wherein each of the time-correlated sums of the workloads monitored on the first storage unit is computed at a respective point in time as a summation of the workloads monitored on the first storage unit at the respective point in time; computing normalized load metrics for the second storage unit based on time-correlated sums of the workloads monitored on the second storage unit over the time interval, each of the workloads monitored on the second storage unit over the time interval being associated with a respective one of the objects stored in the second storage unit, and the monitored performance of the second storage unit, wherein each of the time-correlated sums of the workloads monitored on the second storage unit is computed at a respective point in time as a summation of the workloads monitored on the second storage unit at the respective point in time; and identifying one or more of the objects as candidates for migration between the first storage unit and the second storage unit based on the computed normalized load metrics of the first storage unit and the second storage unit.