1. An apparatus for object placement, comprising: a processor; a non-transitory computer-readable medium storing computer-executable code that the processor executes to: store a number of a plurality of first storages existing in a system; store a number of a plurality of second storages not existing in the system; calculate a first number of layers to distribute the first storage based on the number of the first storage; calculate a second number of layers to distribute the second storage based on the number of the second storage; generate neighboring storage device information including information regarding the first storages whose identifiers are adjacent, for each of layers determined by the first number of layers; generate neighboring non-existing storage device information including information regarding the second storage whose an identifier is adjacent to an identifier of the first storage, for each of layers determined by the second number of layers; and when an object determined by an access command is not stored in own device, search a placement site based on a first vector element that has organized first identifiers for first placement sites existing in a system and on a second vector element that has organized second identifiers for second placement sites not existing in the system, using a fraction of information concerning the first identifiers and a fraction of information concerning the second identifiers, wherein the object is accessed at the placement site that has been determined located as a result of searching, wherein the processor further executes the code to decide the placement site of the object based on the first and second identifiers, and wherein in case the second placement site is designated as the placement site for the object, the processor executes the code to reiterate designating the placement site for the object and confirming existence of the placement site for the object in order to designate the first placement site.