  The majority of works in distributed storage networks assume a simple network
model with a collection of identical storage nodes with the same communication
cost between the nodes. In this paper, we consider a realistic multi-rack
distributed data storage network and present a code design framework for this
model. Considering the cheaper data transmission within the racks, our code
construction method is able to locally repair the nodes failure within the same
rack by using only the survived nodes in the same rack. However, in the case of
severe failure patterns when the information content of the survived nodes is
not sufficient to repair the failures, other racks will participate in the
repair process. By employing the criteria of our multi-rack storage code, we
establish a linear programming bound on the size of the code in order to
maximize the code rate.
