Embodiments relate to a computer system, computer program product, and method to process complex files, and specifically, to support read and write requests of a multi-object file. Upon receipt of a file, a computer system parses the file into two or more logical objects. Each logical object has an associated or inherent characteristic. Each of the logical objects is matched to a storage tier in a multi-tier storage array. Each logical object is then assigned to a tier based on one or more object characteristics in the matched storage tier, and stored in a decomposed format. In addition, an identification of each logical object, and the object assignment, is recorded in an index.