1. A method for depopulation of storage ranks, the method comprising: identifying, by one or more computer processors, at least one source rank selected for depopulation in a storage pool; identifying, by one or more computer processors, one or more source extents for depopulation, wherein the identified one or more source extents belongs to the identified at least one source rank selected for depopulation; obtaining, by one or more computer processors, for each identified source extent of the identified one or more source extents to be depopulated, at least one I/O workload; and sorting, by one or more computer processors, the one or more source extents to be depopulated, based at least in part on the at least one I/O workload for each identified source extent of the identified one or more source extents.