A storage system according to one embodiment includes logic integrated with and/or executable by a hardware processor, the logic being configured to: determine an ownership status for each of a plurality of instances of a file in a first storage tier and in a second storage tier of the storage system; determine locations of the instances of the file in the storage system; determine whether the instances of the file in the first storage tier are being accessed or not being accessed; and assign each of the instances of the file to one of a plurality of indices using the determined ownership status, location, and whether the instances are being accessed.