Provided are a method, system, and article of manufacture, wherein a determination is made that an object corresponding to a first client node has to be stored. A further determination is made as to whether the object has already been sent to a server node by a second client node, wherein the sent object is stored in the server node and is represented by a first entry, and wherein objects and representations of objects stored in the server node form a plurality of groups. The server node receives the object from the first client node, in response to determining that the object has not already been stored in the server node by the second client node. A second entry representing the object is stored at the server node, wherein the second entry references the first entry, in response to determining that the object has already been stored in the server node by the second client node.