1. A method comprising: obtaining data from a storage system by a processor executing instructions out of a memory about an aggregation of storage devices with respect to a specified time period, where the data includes performance data regarding the aggregation of storage devices and configuration data of the storage devices indicating storage device capability for determining input/output performance capability of the aggregation of storage devices; wherein the configuration data includes a number of storage devices in the aggregation and an amount of physical access mechanisms for the storage devices; determining by the processor, with the obtained data about the aggregation of storage devices, a total amount of data transferred for the aggregation of storage devices over the specified time period, input/output performance capability of the aggregation of storage devices, and utilization of the storage devices for servicing requests by the aggregation of storage devices over the specified time period; determining by the processor an aggregate demand value that represents demand on the aggregation of storage devices based on the obtained data, wherein said determining the aggregate demand value comprises determining a product of the utilization of the storage devices for servicing requests by the aggregation of storage devices over the specified time period and a quotient of the total amount of data transferred for the aggregation of storage devices over the specified time period and the input/output performance capability of the aggregation of storage devices that is based on the configuration data; iteratively determining by the processor demand on logical storage containers of the aggregation of storage devices; wherein said determining demand on the logical storage containers of the aggregation of storage devices comprises determining demand on a first logical storage container of the logical storage containers, by determining a logical storage container demand value as a product of a latency value for the first logical storage container and a quotient of a throughput value for the first logical storage container and amount of storage space used by the first logical storage container at a storage device; and using by the processor the determined demand on the logical storage containers of the aggregation of storage devices to manage the aggregation of storage devices such that a high demand logical container is moved to a low demand aggregate of storage devices.