Abstract: A storage system provides shared storage by utilizing dispersed storage devices while optimizing both the placement of data across the dispersed storage devices and the method for accessing the stored data. The storage system enables high level of scalability and performance while minimizing resource consumption.

Abstract: A storage system provides shared storage by utilizing dispersed storage devices while optimizing both the placement of data across the dispersed storage devices and the method for accessing the stored data. The storage system enables high level of scalability and performance while minimizing resource consumption.

Abstract: A storage system provides shared storage by utilizing dispersed storage devices while optimizing both the placement of data across the dispersed storage devices and the method for accessing the stored data. The storage system enables high level of scalability and performance while minimizing resource consumption.

Abstract: A storage system provides shared storage by utilizing dispersed storage devices while optimizing both the placement of data across the dispersed storage devices and the method for accessing the stored data. The storage system enables high level of scalability and performance while minimizing resource consumption.

Abstract: An advanced clock synchronization technique is adapted for use with a replication service in a data backup and recovery storage environment. The storage environment includes a plurality of source storage systems and target storage systems, wherein the source storage systems are illustratively embodied as source replication nodes. The advanced clock synchronization technique establishes a software-only, loosely-accurate global clock based on a timestamp and an associated error boundary. Notably, the timestamp and its error boundary are used as global clock information to enable synchronization (i.e., ordering of storage requests) among the source replication nodes and/or the target storage systems, thereby ensuring consistent replication of the storage requests on the target storage systems.

Abstract: A system and method enhances performance of a log adapted for use with a storage system. The log is illustratively organized into a plurality of regions, wherein each region comprises one or more entries and wherein each region is allocated to a consistency collection. As used herein, a consistency collection is defined as a set of one or more data containers among which it is desired to maintain transaction consistency, i.e., atomicity of updates of a transaction to those containers. Each entry of the region is adapted to store an update of data from a source, e.g., an application executing on the storage system. Thus, the consistency collection may comprise multiple data containers associated with one or more applications configured to maintain the atomicity of transaction updates to the collection of containers.

Abstract: A write ordering style asynchronous replication service utilizes a loosely-accurate global clock in a data backup and recovery storage environment. The storage environment includes a set of source storage systems illustratively embodied as source replication nodes that cooperate to maintain a consistency group that may span multiple geographical sites. The storage environment also includes one or more target storage systems illustratively embodied as target replication nodes configured to service the consistency group. The write ordering style service utilizes the loosely-accurate global clock to provide consistent replication of a storage space of the consistency group.

Abstract: A delta query technique transmits only latest changes to data of objects from a server to one or more clients in response to a client query (request) to access the object data. A global counter is maintained for all of the objects served by the server. Every time the data of an object changes, a value of the global counter increments (updates) and the updated global counter value is then assumed (“inherited”) by that object. In addition, the global counter is updated when a client issues a request to access one or more objects. If the data of the objects has changed since the last time the client accessed the objects, the server responds with the latest object data and the updated global counter value. Notably, each client maintains a local counter having a value that, upon receipt of the latest object data, is modified to reflect the updated global counter value.

Abstract: A system and method enhances performance of a log adapted for use with a storage system. The log is illustratively organized into a plurality of regions, wherein each region comprises one or more entries and wherein each region is allocated to a consistency collection. As used herein, a consistency collection is defined as a set of one or more data containers among which it is desired to maintain transaction consistency, i.e., atomicity of updates of a transaction to those containers. Each entry of the region is adapted to store an update of data from a source, e.g., an application executing on the storage system. Thus, the consistency collection may comprise multiple data containers associated with one or more applications configured to maintain the atomicity of transaction updates to the collection of containers.

Abstract: A write ordering style asynchronous replication service utilizes a loosely-accurate global clock in a data backup and recovery storage environment. The storage environment includes a set of source storage systems illustratively embodied as source replication nodes that cooperate to maintain a consistency group that may span multiple geographical sites. The storage environment also includes one or more target storage systems illustratively embodied as target replication nodes configured to service the consistency group. The write ordering style service utilizes the loosely-accurate global clock to provide consistent replication of a storage space of the consistency group.

Abstract: An advanced clock synchronization technique is adapted for use with a replication service in a data backup and recovery storage environment. The storage environment includes a plurality of source storage systems and target storage systems, wherein the source storage systems are illustratively embodied as source replication nodes. The advanced clock synchronization technique establishes a software-only, loosely-accurate global clock based on a timestamp and an associated error boundary. Notably, the timestamp and its error boundary are used as global clock information to enable synchronization (i.e., ordering of storage requests) among the source replication nodes and/or the target storage systems, thereby ensuring consistent replication of the storage requests on the target storage systems.

Abstract: A data backup and recovery system for use with at least one server interconnected with at least one storage device, including at least one data recovery device, at least one associated data recovery storage device, controlled by the data recovery device, and at least one data communication monitor. A method for data backup and recovery is also disclosed.

Abstract: A target data storage system comprises a peer-to-peer communication link interface for linking the target to a source data storage system, and data storage for storing point in time copy data received from the source via the peer-to-peer communication link interface. Information is established at the target relating logical identification of the point in time copy data to point in time copy data stored at the target and to point in time copy data stored at the source, such that the information references the data storage system having requested point in time copy data. A controller of the target accesses requested point in time copy data at the target if the table indicates that the requested point in time copy data is available at the target; else obtains the requested point in time copy data from the source via the peer-to-peer communication link interface.

Abstract: A data backup and recovery system for use with at least one server interconnected with at least one storage device, including at least one data recovery device, at least one associated data recovery storage device, controlled by the data recovery device, and at least one data communication monitor. A method for data backup and recovery is also disclosed.

Abstract: A target data storage system comprises a peer-to-peer communication link interface for linking the target to a source data storage system, and data storage for storing point in time copy data received from the source via the peer-to-peer communication link interface. Information is established at the target relating logical identification of the point in time copy data to point in time copy data stored at the target and to point in time copy data stored at the source, such that the information references the data storage system having requested point in time copy data. A controller of the target accesses requested point in time copy data at the target if the table indicates that the requested point in time copy data is available at the target; else obtains the requested point in time copy data from the source via the peer-to-peer communication link interface.

Abstract: A method for data backup includes creating a sidefile in a cache memory of a data storage system. Entries are added to the sidefile specifying copy operations to be respectively performed by copy services in the system, including at least first and second copy services of different, first and second types. The copy operations specified by the operations are then executed using the first and second copy services.

Abstract: A method that uses a single callback function for a multiphase service with possible discontinuation of execution between the phases. The method is based on assignment of a case in the callback function for each phase or state of the service and a stack of state descriptors. At each call to the callback function, the top descriptor is popped off the stack and the appropriate case in the callback function is run.

Abstract: System for the storage and maintenance of data sets updates in a storage subsystem, that comprises direct access storage device(s) that serves as the main storage of the storage subsystem and on which the data sets are originally stored; a Cache memory storage device that enables fast interaction with the storage subsystem, on which a copy of the data sets is stored; a non-volatile storage device partitioned into a plurality of fixed size non-volatile memory pages.

Abstract: Disclosed is a method, system, program, and data structures for maintaining electronic data at a point-in-time. A first data structure indicates point-in-time data at one of a first storage location and a corresponding second storage location. A second data structure indicates point-in-time data at one of a first storage location and corresponding second storage location. A first relationship data structure indicates a relationship between the first storage location and corresponding second storage location and a second relationship data structure indicates a relationship between the first storage location and second storage location. A request to process the first storage location is processed by processing the first relationship data structure to determine the corresponding second storage location for the first storage location and processing the first data structure to determine whether data at the first storage location was transferred to the second storage location.

Abstract: A method that uses a single callback function for a multiphase service with possible discontinuation of execution between the phases. The method is based on assignment of a case in the callback function for each phase or state of the service and a stack of state descriptors. At each call to the callback function, the top descriptor is popped off the stack and the appropriate case in the callback function is run.