1. A distributed data storage system comprising: a plurality of physical storage volumes for storing a plurality of files of data accessible by a single file system; a network; and a plurality of storage nodes, coupled to said network, each one of said storage nodes having access to each of said files stored on said physical storage volumes, the files of data being distributed across the plurality of physical storage volumes to provide a single system image to the plurality of storage nodes, each file associated with one of the plurality of storage nodes and wherein each of said storage nodes for receiving a request from a client for a storage operation on a file identified in said single system image, said file managed by another storage node, upon receiving said request by a receiving storage node, the receiving storage node communicating with said other storage node to obtain a lock for said file from said other storage node, upon receiving said lock, said receiving storage node processing said storage operation by accessing at least one of said physical storage volumes, and transmitting a response for said storage operation to said client; a storage node comprising: a distributed file system manager for processing said client requests for storage operations; and a volume manager to read data from and/or to write data to said physical volumes; the distributed data storage system also comprising a layer-4 load balancing switch, coupled to said network, for receiving said request from a client for a storage operation and for selecting one of said storage nodes to process said storage operation, the layer-4 load balancing switch being to prioritize transport layer protocol traffic and distribute application protocol layer sessions, the one of the storage nodes to obtain an inode for a root directory and to transmit to the client a file handle to the root directory, the file handle to be used by the client to access the file identified in said single system image, each of the storage nodes to store a map manager data structure, the map manager data structure including a table correlating respective ranges of inodes in the distributed data storage system with respective nodes in the distributed data storage system that manage the respective ranges.