Abstract: A storage server obtains metadata to describe a filesystem, then processes the metadata to locate a data block and reads the data block from a remote storage subsystem. Apparatus and software implementing embodiments of the invention are also described and claimed.

Abstract: Embodiments of this invention disclose a file system having a hybrid file system format. The file system maintains certain data in two formats, thereby defining a hybrid file system format. In one exemplary application, the first format has properties favorable to write operations, e.g. a log-structured file system format, while the second format has properties favorable to read operations, e.g. an extent-based file system format. The data is stored in the first file system format and then asynchronously stored in the second file system format. The data stored in the second file system format are also updated asynchronously.

Abstract: An embodiment of the invention provides an apparatus that includes a primary node, a secondary node, and an intermediate node. Data is synchronously copied from the primary node to the intermediate node, and data is asynchronously copied from the intermediate node to the secondary node. The data stored in the intermediate node is a subset of the data set that is stored in the primary node. Therefore, an embodiment of the invention advantageously provides a multiple hop data replication method that allows data recovery if disaster occurs at the location of the primary node. Additionally, an embodiment of the invention advantageously provides a tolerable latency value from the time that a client device sends a write request to the primary node to the time that an acknowledgement message is received by the client device.

Abstract: A method for operating a data storage system is described. A request is issued that an ownership attribute of a logical arrangement of storage space associated with a first storage system be associated with a second storage system. In response to the request, the ownership attribute is changed to a state of unowned. In response to the request and in response to the state of unowned, the ownership attribute of the logical arrangement of storage space is changed to a new set of attributes associated with the second storage system to change ownership of the logical arrangement of storage space from the first storage system to the second storage system.

Abstract: A filer converts a traditional volume to a flexible volume by: creating an aggregate on storage devices other than the storage devices of the traditional volume; on the aggregate, creating a flexible volume large enough to store metadata describing files residing on the traditional volume; on the flexible volume, creating metadata structures that describe the files of the traditional volume, except that the metadata indicates that data blocks and indirect blocks are absent and must be fetched from another location. As the filer handles I/O requests directed to the flexible volume, the filer calculates physical volume block number (PVBN) addresses where the requested blocks would be located in the aggregate and replaces the absent pointers with the calculated addresses. After the absent pointers have been replaced, the filer adds the storage devices of the traditional volume.

Abstract: A storage server obtains metadata to describe a filesystem, then processes the metadata to locate a data block and reads the data block from a remote storage subsystem. Apparatus and software implementing embodiments of the invention are also described and claimed.

Abstract: Data storage methods and apparatus combining read-only and read-write storage are described. Data may be located by information maintained in a filesystem; each data block is stored in either the read-only storage or the read-write storage.

Abstract: A system and method for a file server to allocate spare disks in a network storage system. The method determines the available spare disks and first selects those disks that satisfy one or more required rules. The method sorts the spare disks by a set of ordered policies to determine a highest-ranked disk that is then selected as the spare to be utilized. If multiple disks are equally ranked, one of the equally ranked disks is randomly chosen to be the spare disk allocated.

Abstract: An embodiment of the invention provides an apparatus that includes a primary node, a secondary node, and an intermediate node. Data is synchronously copied from the primary node to the intermediate node, and data is asynchronously copied from the intermediate node to the secondary node. The data stored in the intermediate node is a subset of the data set that is stored in the primary node. Therefore, an embodiment of the invention advantageously provides a multiple hop data replication method that allows data recovery if disaster occurs at the location of the primary node. Additionally, an embodiment of the invention advantageously provides a tolerable latency value from the time that a client device sends a write request to the primary node to the time that an acknowledgement message is received by the client device.

Abstract: A system and method for reliable peer-to-peer communication is provided. The system and method includes a cluster connection manager that acts as a unified resource for opening, closing and maintaining peer-to-peer communication channels between applications executing on storage systems comprising a storage system cluster. The cluster connection manager communicates with cluster connection manager clients to maintain and manage the communication channels. The cluster connection manager may also be operatively interconnected with a plurality of cluster interconnect devices, thereby enabling failover operation in the event that a cluster interconnect device suffers an error condition.

Abstract: A system and method for reliable peer-to-peer communication is provided. The system and method includes a cluster connection manager that acts as a unified resource for opening, closing and maintaining peer-to-peer communication channels between applications executing on storage systems comprising a storage system cluster. The cluster connection manager communicates with cluster connection manager clients to maintain and manage the communication channels. The cluster connection manager may also be operatively interconnected with a plurality of cluster interconnect devices, thereby enabling failover operation in the event that a cluster interconnect device suffers an error condition.