There is disclosed a method for writing data in a data storage system comprising a plurality of data storage nodes, the method being employed in a server running an application which accesses data in the data storage system, and comprising: sending a multicast storage query to a plurality of said storage nodes; receiving a plurality of responses from a subset of said storage nodes, said responses including a storage node property; selecting at least two storage nodes in the subset for storing said data, based on said responses, wherein the selecting is based on a data property of the data to be stored and a storage node property.