Abstract: Preventing duplicate entries of identical data in a storage device, including: receiving a write request to write data to the storage device; calculating one or more signatures for the data associated with the write request; determining whether any of the calculated signatures match a calculated signature contained in a recently read signature buffer, each entry in the recently read signature buffer associating a calculated signature for data that has been read with an address of a storage location within the storage device where the data is stored; and responsive to determining that one of the calculated signatures matches a calculated signature contained in the recently read signature buffer, determining whether the data associated with the calculated signature is a duplicate of data stored at a particular address that is associated with the calculated signature contained in the recently read signature buffer.

Abstract: Preventing duplicate entries of identical data in a storage device, including: receiving a write request to write data to the storage device; calculating one or more signatures for the data associated with the write request; determining whether any of the calculated signatures match a calculated signature contained in a recently read signature buffer, each entry in the recently read signature buffer associating a calculated signature for data that has been read with an address of a storage location within the storage device where the data is stored; and responsive to determining that one of the calculated signatures matches a calculated signature contained in the recently read signature buffer, determining whether the data associated with the calculated signature is a duplicate of data stored at a particular address that is associated with the calculated signature contained in the recently read signature buffer.

Abstract: Systems, apparatuses, methods, and computer-readable storage mediums for performing lease-based fencing using a time-limited lease window. During the time-limited lease window, writes to a shared storage medium are permitted, while writes are denied for expired leases. When a successful heartbeat is generated for a primary storage controller, the lease window is extended for the primary storage controller from the time of a previous heartbeat. Accordingly, a prolonged stall between successive heartbeats by the primary storage controller will result in the newly extended lease being expired at the time it is granted. This scheme prevents a split brain scenario from occurring when a secondary storage controller takes over as the new primary storage controller in response to detecting the stall.

Abstract: Systems, apparatuses, methods, and computer-readable storage mediums for performing lease-based fencing using a time-limited lease window. During the time-limited lease window, writes to a shared storage medium are permitted, while writes are denied for expired leases. When a successful heartbeat is generated for a primary storage controller, the lease window is extended for the primary storage controller from the time of a previous heartbeat. Accordingly, a prolonged stall between successive heartbeats by the primary storage controller will result in the newly extended lease being expired at the time it is granted. This scheme prevents a split brain scenario from occurring when a secondary storage controller takes over as the new primary storage controller in response to detecting the stall.

Abstract: Preventing duplicate entries of identical data in a storage device, including: receiving a write request to write data to the storage device; calculating one or more signatures for the data associated with the write request; determining whether any of the calculated signatures match a calculated signature contained in a recently read signature buffer, each entry in the recently read signature buffer associating a calculated signature for data that has been read with an address of a storage location within the storage device where the data is stored; and responsive to determining that one of the calculated signatures matches a calculated signature contained in the recently read signature buffer, determining whether the data associated with the calculated signature is a duplicate of data stored at a particular address that is associated with the calculated signature contained in the recently read signature buffer.

Abstract: Systems, methods, and computer readable storage mediums for optimistically managing compressed data in a storage system. When possible, multiple input blocks are compressed into a buffer and stored in a single physical block on a storage device. The metadata of the multiple input blocks can be managed separately. A fingerprint of the compressed buffer can be generated and used as an index to the single physical block. Alternatively, fingerprints of the uncompressed input blocks can be generated, and reference counts can be maintained to track the number of input blocks which reference the compressed buffer.

Abstract: A method involves: detecting a storage resource indication within a workflow request and, in response to the storage resource indication, generating an availability indication. The storage resource indication indicates a storage resource (e.g., by directly or indirectly identifying or selecting the storage resource). The availability indication indicates that the indicated storage resource is not available for subsequent workflow requests. The availability indication is generated prior to allowing the consumer that generated the workflow request to use the storage resource. The workflow request can include a request to allocate a logical storage structure (e.g., a volume or logical disk). The logical storage structure is allocated in response to the workflow request. If the workflow request is denied or expires, the logical storage structure is deleted.

Abstract: A method and system for providing a shared data resource coordinator within a storage virtualizing data processing system is disclosed. According to one embodiment of the present invention, a first node of a plurality of nodes is configured to process requests to access a shared data resource on behalf of the plurality of nodes, where the plurality of nodes includes a logical volume configuration server configured to present a logical volume to one or more logical volume configuration clients. A second node is then selected from the plurality of nodes and configured to process requests to access the shared data resource on behalf of the plurality of nodes.

Abstract: A method and system of providing a virtual transport session is disclosed. According to one embodiment, a virtual transport session is provided by establishing a virtual transport session between an initiator module and a target module across a network, wherein the virtual transport session comprises a transport session. Thereafter, information is transferred between the initiator module and the target module using the virtual transport session. According to another embodiment, establishing a virtual transport session between an initiator module and a target module across a network comprises associating a globally unique identifier to an initiator module.

Abstract: Applications executing on various nodes in a distributed storage environment may write data to primary storage and may also replicate the data to secondary storage via a replication target. An interval coordinator may coordinate the periodic saving of checkpoints or snapshots of the replicated data. The interval coordinator may determine the length of consistency intervals between the saving of each of the checkpoints. Writes to the replication target from each of the nodes may be associated with the current consistency interval and, in some embodiments, with a unique per-node sequence number. When transitioning between consistency intervals, each node may be configured to temporarily suspend completion of the writes and to send the replication target a consistency interval marker indicating that the node has completed all writes for the current consistency interval.

Abstract: Configuration data, such as options a file system accessed by a host system, may be stored on the storage device storing the file system. File system configuration data may be stored in a file of the file system or in a private storage area configured for storing file system configuration data. A host may access the file system configuration data and subsequently may access the file system according to the file system configuration data. Additionally, different versions of file system configuration data may be stored and different hosts accessing the file system may read and use different versions of the file system configuration data based upon the type or context of the host accessing the file system. Storing file system configuration data with the file system data, or on the same storage device, may allow context dependent options to be provided to various hosts accessing the file system data.

Abstract: In-band commands may be associated with a particular consistency interval and may indicate requested actions to be performed for that consistency interval. An application may desire to perform actions, such as additional backup, snapshots, etc. on stored data, when that data is in a consistent state from the application's point of view. In order to ensure that the data is in a consistent state, a consistency interval may be created on demand. A node may request a consistency interval by sending a consistency request message to a consistency interval coordinator, which in turn, establishes the consistency interval with all nodes in the distributed environment. After sending all write requests for the consistency interval, the node may then send the command message. Command messages may be stored in consistency logs along with write requests and a replication target, or other device, may read both the write requests and the command message.

Abstract: A system for ensuring availability using volume server sets in a storage environment employing distributed block virtualization includes a plurality of volume servers, one or more volume clients, one or more physical block devices and a volume server manager. The volume server manager may be configured to designate the plurality of volume servers as a volume server set with an associated volume server set management policy, and to verify each volume server in the volume server set has access to storage within each block device. In addition, the volume server manager may be configured to designate a first volume server of the volume server set to aggregate storage within the block devices into a logical volume, to make the logical volume accessible to the volume clients, and to share configuration information about the volume with the other volume servers of the volume server set.

Abstract: A method for revocable token identifiers may be employed in a shared storage environment. An access server may generate access tokens and include revocable token identifiers previously obtained from storage devices. When clients present access tokens to storage devices during storage requests, storage devices may check the validity of access tokens by verifying that the revocable token identifiers were previously issued to the access server. An access server may request that the storage device revoke revocable token identifiers. Storage devices may deny any future storage requests including revoked token identifiers. Additionally, an access token may include instructions specifying operations for a storage device to perform in conjunction with a storage request. A trusted server may issue grantor tokens granting permissions for access servers to use when issuing access tokens. An access server may then include such a grantor token in access tokens that it generates and issues to clients.

Abstract: A computer system that implements a method for creating a virtual snapshot of a first storage object. A first storage object such as a data volume is created, wherein creating the first storage object includes creating a first storage object description. This first storage object description relates the first storage object to underlying first storage objects or first physical memory regions. After creating the first storage object, a virtual copy of the first storage object is created as a second storage object. Creating the second storage object includes creating a second storage object description, wherein the second storage object description relates the second storage object to the first storage object. The first storage object is transmitted to a first computer system, and the second storage object description is transmitted to a second computer system.

Abstract: A method, system, computer system, and computer-readable medium for maintaining up-to-date, consistent copies of primary data without the need to replicate modified data when the data were modified as a result of an operation that is not an application-driven write operation captured during replication. Selected storage management operations are performed on the primary and secondary data stores at points in time when the data are the same to ensure that the data stored within the data stores remain consistent. These selected storage management operations include operations that produce modified data stored in the primary data store, where a portion of the modified data are not replicated to a secondary node. Other types of storage management operations are selected to be performed on both the primary and secondary data stores, where the operations do not directly change data in the primary data store, but may affect data stored in the primary data store.

Abstract: A method and apparatus for configuring a user interface is disclosed. The method and apparatus allow for the determination of a function provided by the user interface using a skin. Such a skin includes information regarding an object, where the object represents an entity managed using the user interface.

Abstract: Disclosed is a method implementable by a computer system for maintaining consistency between mirrors of a mirrored data volume. In one embodiment, the method includes the computer system generating first and second write transactions in response to the generation of transaction to write data to a mirrored data volume. The first and second write transactions comprise first and second tags, respectively. The first and second tags relate the first write transaction to the second write transaction. In one embodiment, the first and second tags are identical. After the first and second write transactions are generated, the computer system transmits the first and second write transactions to first and second storage subsystems, respectively. In one embodiment, the first and second storage subsystems store or are configured to store respective mirrors of the data volume.

Abstract: In distributed storage environments, nodes may send replicated writes for temporal volumes and may be configured to request on-demand consistency intervals in order to allow multiple nodes to transition between timestamps for temporal data in a uniform and coordinated manner. In response to a request from a node for a consistency interval transition, a consistency interval coordinator may end a current consistency interval and start another and may provide coordination to various nodes to enable the nodes to transition from one timestamp to another, and thus from one temporal version to another, while prevent data corruption or inconsistency between the temporal versions. Additionally, periodic consistency intervals may be utilized to provide consistent and coordinated transitions between temporal timestamps. In some embodiments, replicated writes including temporal timestamp information may be stored persistent spillover logs allowing offline updating and versioning of data to temporal volumes.

Abstract: A computer system or memory medium with instructions executable by a computer system to use a single allocator to coordinate volume transformations across virtualization layers. In one embodiment, the computer system creates a first storage object, wherein the first storage object is created to have a property. The computer system creates a second storage object out of the first storage object, wherein the second storage object depends on the property of the first storage object. The computer system then modifies the first storage object, wherein the modified first storage object maintains the property upon which the second storage object depends.