EXPANDING THE STORAGE CAPACITY OF A VIRTUALIZED DATA STORAGE SYSTEM

A system, method, apparatus, and computer-readable medium are provided for expanding the data storage capacity of a virtualized storage system, such as a storage cluster. According to one method, maps are generated and stored that define a stripe pattern for storing data on the storage nodes of a storage cluster. The stripe pattern for each map is defined such that when a storage node is added to a cluster and the data is re-striped according to the new map, only the data that will subsequently reside in the new storage node is moved to the new storage cluster during re-striping. The stripe pattern may be further defined so that during re-striping no movement of data occurs between two storage nodes that existed in the cluster prior to the addition of the new storage node. The stripe pattern may be further defined such that during re-striping an equal amount of data is moved from each of the storage nodes that existed in the cluster prior to the addition of the new storage node to the new storage node.