Abstract: A NAS (Network Attaches Storage) switch authenticates a client on multiple file servers for proxy services. The NAS switch enables proxy services by successively authenticating the client on the file servers using referrals. The NAS switch further comprises a connection manager to establish connections to the client and the file servers, a referral manager to redirect the client for successive authentications, and a transaction manager to perform data transfers with the file servers on behalf of the client. The system components support DFS (Distributed File System), and communicate using a protocol dialect that supports referral mechanisms such as NFSv4 (Network File Server version 4) or CIFS (Common Internet File System). The transaction manager also performs a protocol dialect translation service when the connection manager negotiates one protocol dialect with the client, and a different protocol dialect with the file server.

Abstract: A NAS switch provides file migrations in a NAS storage network that are transparent to the clients. A source file server exports an original NAS file handles indicative of object locations on the source file server to the NAS switch. The NAS switch modifies the original NAS file handles to an internal file system and maps the original NAS file handles to a switch file handles independent of location. The NAS switch exports the switch file handles to a client. The client looks-up objects and makes NAS requests to the source file server using switch file handles. The NAS switch performs file migration by first replicating the namespace containing data to be migrated from source file server to a destination file server. Separately, the NAS replicates data which is a relatively longer process than the namespace replication. During data replication, namespace access requests for objects are directed to the replicated namespace.

Abstract: A NAS switch provides extended storage capacity to a file server in a decentralized storage network such as a NAS (Network Attached Storage) storage network. The NAS switch sits in the data path of a client on the front end and a directory file server and shadow file servers on the back end. A segregation module in the NAS switch replicates data from the directory file server to a shadow file server, and then replaces the data in the directory file server with holey files. Holey files, which store a range of consecutive values such as zero with negligible storage space, retain the attributes of the data without retaining its storage consumption. Thus, the directory file server can server as a single directory hierarchy for several shadow file servers containing data beyond a capacity of the directory file server. When the NAS switch receives operations from the client, an association module forwards directory operations to the directory file server and data operations to the shadow file server.

Abstract: A NAS switch provides large file support to a file server in a decentralized storage network such as a NAS (Network Attached Storage) storage network. For example, files greater than 2-GB can be stored on a 32-bit commodity file server. The NAS switch sits in the data path of a client on the front end and a commodity NAS file server on the back end. A segmentation module in the NAS switch stores large files as separate data chunks in the file server. To do so, the segmentation module stores a directory file handle, which points to a directory containing the data chunks, in place of the large file. The segmentation module can also store a large file/chunk directory association in a migration cache. A reconstruction module processes client requests concerning large files by issuing requests to specific data chunks. For example, in a read operation, the reconstruction module calculates chunk numbers to determine which file to read and offsets to determine which byte to read within a chunk.

Abstract: A NAS switch, in the data path of a client and a NAS file server on the storage network, provides a centralized point of reconfiguration after a network change that alleviates the need for reconfiguration of each connected client. The client uses a NAS request to access a storage object to the NAS switch using a switch file handle that is independent of object location and that can be used to locate the primary and its replica storage objects if the object is subsequently replicated. A replication module replicates a namespace separately from data contained therein. Afterwards, synchronicity module looks-up the switch file handle in a file handle replication table to determine if the object has been replicated and, if so, sends one of the replica NAS file handles. The synchronicity module also maintains synchronicity between the primary and replica file servers through critical NAS requests that modify objects such as create, delete, and the like.