text: File-based data storage systems are known in the art. These systems include programming and hardware structures to provide file-based access to file systems. File-based data storage systems are sometimes referred to as Network Attached Storage or NAS systems. Such systems may support NFS (Network File System), CIFS (Common Internet File System), SMB (Server Message Block), and/or other file-based protocols. With file-based protocols, host computers (hosts) perform read and write operations to files by specifying particular file systems, paths, and file names. Internally to the data storage system, file system directories map the files specified by host commands to particular sets of blocks on internal volumes, which themselves are derived from disk drives or electronic flash drives. The data storage system accesses the mapped locations and performs the requested reads or writes. An example of a file-based data storage system is the Celerra® system from EMC Corporation of Hopkinton, Mass.