Abstract: The present invention provides a novel influenza virus wherein both the NS and the PB1 gene segments are modified and wherein the PB1-F2 open reading frame is modified by introduction of at least one stop codon. Specifically, the influenza virus is lacking functional NS1 and PB1-F2 proteins. Additionally, a vaccine formulation comprising said modified influenza virus is provided and its use for prevention of influenza infection.

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, system, and computer-readable medium to maintain consistent, up-to-date copies of primary data. Primary data is maintained on a primary node, and point-in-time snapshots of the primary data are maintained on a secondary or remote node. Read operations can be directed to read some or all data from the remote node. When part of the data on the primary node becomes unavailable due to corruption, device failure, or communication failure, unavailable data can be read from the secondary node. When the determination is made that an unavailable portion of the data exists, a third data storage accessible by the first host can be created. Each subsequent change to the data in the first data storage can be written only to the third data storage. If an updated portion of the data is to be read, the updated portion can be read from the third data storage.

Abstract: A system and method for storing data. In one embodiment, a file system includes a hierarchy of nodes partitioned into a plurality of containers. The file system further includes metadata associated with each node. First metadata describes each node's references to other nodes and second metadata identifies each node's parent node. The file system further includes a linkage table associated with each container. Each linkage table comprises entries describing links between a node owned by the associated container and other nodes. In response to detecting that a file system error has occurred, the file system identifies a container which corresponds to the detected error, corrects inconsistencies between the first and second metadata associated with each node owned by the container, and corrects inconsistencies between each of the entries of the linkage table associated with the identified container and the first and second metadata.

Abstract: A set of probabilities may indicate the chance of finding the latest version of a data item in any particular data image layer of a data image. A client may use the set of probabilities to request the data item from one or more layers that have a higher probability of having that version of the data item. A client may query more recently created layers to determine whether they have a version of the data item. If any of the more recently created data image layers has a version of the data item, a client may request the data item from the most recent of the more recently created layers and may discard any data returned from the originally requested layer. A client may update the historical probabilities based on which layers contain versions of the data item.

Abstract: A system and method for data storage in an array. A system includes a client coupled to a storage subsystem. The storage subsystem comprises data storage locations addressable as rows and columns in an array. Each column comprises a separate storage device. Each row includes redundant data. For a given row, a coordinating storage device receives data from the client, coordinates computation and storage of redundant data, and forwards data to other storage devices. In response to receiving data targeted for storage in a given storage location, a non-volatile, temporary storage device that is associated with the separate storage device that includes the given storage location buffers the received data. The coordinating storage device conveys a write completion message to the client in response to detecting that the data has been buffered in the non-volatile, temporary storage devices. At least two storage devices are coordinating storage devices in separate rows.

Abstract: A system and method for detecting mirror inconsistencies in a distributed storage environment. Inconsistencies between mirrors may be detected by comparing session tags among individual storage devices. Each data write may include a tag and storage devices may calculate session tags from the write tags. Additionally, a storage device may keep a history including tags from recent writes. When a client sessions ends, a metadata server may compare the respective session tags from different storage devices to determine whether the mirrors are synchronized. If the session tags do not match, the metadata server may examine the metadata histories from the storage devices to determine a cause for the discrepancy in the session tags. If examining the session histories fails to reveal the discrepancy's source, a metadata server may request individual data block checksums from storage devices to attempt a re-synchronization of the mirrored storage devices.

Abstract: A system and method of characterizing a logical storage object. Information associated with the logical storage object is stored. The information includes information characterizing quiesce capabilities and split characteristics for the logical storage object. That information is transmitted to a processor and is used to characterize the logical storage object.

Abstract: Various systems and methods for performing coordinated distributed write logging are provided. A method may involve one of several hosts, each of which has an associated log, requesting permission to perform a write to data in a storage volume from a coordinator. The coordinator coordinates access to the storage volume between the hosts. Prior to receipt of a response from the coordinator granting permission to perform the write to the storage volume, the host may initiate logging the write data for the write to a respective log. The host may signal completion of the write to an application that initiated the write in response to both logging the write data to the respective log and receiving the response from the coordinator. The host may perform one or more underlying block operations to update the storage volume according to the write subsequent to signaling completion of the write to the application that initiated the write.

Abstract: In a process to restore a data volume in a first memory, a virtual point-in-time (PIT) copy of the data volume is created. Creating the virtual PIT copy includes creating first, second and third maps in memory. Each of the first, second, and third maps includes a plurality of multi-bit entries. Each of the entries of the first and second maps corresponds to a respective memory region of the first memory, while each of the entries of the third map corresponds to a respective memory region of a second memory for storing data of the virtual PIT copy.

Abstract: A system and to prevent data corruption due to split brain in shared data clusters includes two or more nodes of a cluster, a shared storage device, and an update manager. The update manager may be configured to maintain a local persistent store corresponding to each node of the cluster. On receiving an update request directed to the shared storage device from a first node, the update manager may be configured to redirect the update to the local persistent store corresponding to the first node. The update manager may be further configured to verify a cluster membership status of the first node, and to transfer the contents of the update from the local persistent store to the shared storage device if the cluster membership verification succeeds.

Abstract: Systems, methods, apparatus and software can make use of separated I/O processors and strategy processors (implemented in hardware and/or software) to perform virtual device I/O operations. I/O processors operating on cluster nodes, storage appliance ports, or other devices can receive I/O operation requests directed to virtual devices, e.g., volumes or virtual logical units. Information about the request is forwarded to a strategy processor, operating independently or as part of larger volume management software where corresponding physical device I/O operations are determined. The physical device I/O operations can include additional information about the operations, e.g., tag information and summary information, for use in processing the virtual device I/O request. The physical device I/O operations are sent back to the I/O processor which executes the operations and/or passes the operation on to the appropriate storage device.

Abstract: Data from a first mirror of a data volume is returned to the computer system in response to receiving the first read request. Additionally, data from second mirror of the data volume is read in response to receiving the first read request. The data read from the second mirror may be stored in a cache memory. The computer system may check the returned data to determine whether it is corrupted. If corrupted, the computer system sends a second read request for the same data. Rather than returning the same corrupted data stored in the first mirror, a copy of the requested data is returned from the cache memory.

Abstract: Systems, methods, apparatus and software can implement a multipathing driver using dynamically loadable device policy modules that provide device specific functionality for providing at least one of input/output (I/O) operation scheduling, path selection, and I/O operation error analysis. Because the device policy modules include device specific functionality, various different devices from different manufacturers can be more efficiently and robustly supported.

Abstract: A system and method for storing data. In one embodiment, a file system stores data including associated metadata. In response to detecting that a file system error has occurred, the file system identifies a container including data in which the error occurred and performs a consistency check of the data included in the container. If a bidirectional link exists between the container and another container and if an error is found in the bidirectional link, the file system performs a consistency check of data included in the other container and determines if another bidirectional link exists between the other container and a third container. If another bidirectional link exists between the other container and a third container and if an error is found in the other bidirectional link, the file system performs a consistency check of data included in the third container.

Abstract: Disclosed is an apparatus and method for transforming unrelated data volumes into related data volumes. The present invention is employed after creation of first and second unrelated data volumes. In one embodiment, the second data volume is refreshed to the data contents of the first data volume so that the second data becomes a PIT copy of the first data volume. Refreshing the second data volume includes overwriting all data of the second data volume with data copied from the first data volume. However, before all data of the second data volume is overwritten with data copied from the first data volume, data of the first data volume can be modified.

Abstract: A file system may employ an enhanced or performance-adjusted allocation scheme when storing data to multiple storage devices. A file system may monitor one or more performance characteristics of storage devices. The file system may, in response to storage requests, select one or more of the storage devices for storing data associated storage requests based on differences among the respective monitored performance characteristics for the storage devices. Additionally, the file system may determine an allocation pattern for storing data to the storage devices and may modify the determined allocation pattern based on a detected change in the monitored performance characteristics of the storage devices. Further, the file system may store data based on both the allocation pattern and on data characteristics associated with a data storage request. The file system may also incorporate input specifying either new performance characteristics or a new allocation pattern.

Abstract: Systems, methods, apparatus and software can make use of coordinator resources and SCSI-3 persistent reservation commands to determine which nodes of a cluster should be ejected from the cluster, thereby preventing them from corrupting data on a shared data resource. Fencing software operating on the cluster nodes monitors the cluster for a cluster partition (split-brain) event. When such an event occurs, software on at least two of the nodes attempts to unregister other nodes from a majority of coordinator resources. The node that succeeds in gaining control of the majority of coordinator resources survives. Nodes failing to gain control of a majority of coordinator resources remove themselves from the cluster. The winning node can also proceed to unregister ejected nodes from shared data resources. These operations can be performed in parallel to decrease failover time. The software can continue to execute on all nodes to prevent additional problems should a node erroneously attempt to reenter the cluster.

Abstract: A system employing asymmetric distributed block virtualization includes a volume server, a plurality of volume clients, and one or more physical block devices. The volume server aggregates storage in the physical block devices into a logical volume and makes the logical volume accessible to the volume clients for input/output (I/O) operations. In order to manage different I/O access requirements (such as read-only access versus read-write access) of the volume clients, the volume server maintains a different I/O access policy for each volume client to control the kinds of input/output operations that the volume client is allowed to perform on the logical volume.

Abstract: A method, system, computer system and computer program product to synchronize data and a snapshot of the data taken at a given point in time. Persistent data change maps are used to track changes made to data after a snapshot of the data is taken. Changes to the data are tracked using a persistent accumulator map, and changes to the data with respect to a second set of data are tracked using a persistent volume map. The persistent accumulator map is updated with each update of the data. Persistent volume maps are updated when a subsequent snapshot of the data is taken. Only changes to the data made after the snapshot was taken are applied to synchronize the snapshot with the data so that all of the data is not copied. Snapshots can be located in a physically separate location from the data itself.