Abstract: A composite storage server employs a plurality of distributed storage sites including a mount site, a source copy site and one ore more copy target sites for executing a storage of volume data within the composite storage server. In operation, a deferred copy target site receives a communication of a source copy complete message from the mount site, the source copy complete message being indicative of the source copy site having a complete copy of the volume data, and detects a transition by the mount site of the host job from an active status to an inactive status subsequent to the communication of the source copy complete message from the mount site. Based on the inactive status of the host job, the deferred copy target site pulls the volume data from a peer distributed storage site having a complete copy of the volume data.

Abstract: An embodiment of the invention comprises a virtual tape system supporting at least one Write Once Read Many (WORM) logical tape and at least one read-write logical tape, comprising a processor configured to a first task and/or a second task. The first task initializes a new logical data object from a single pool of at least two logical data objects, with the new logical data object bound with a member of a media type group consisting of a WORM data object or a read-write data object. The second task reuses one of the logical data objects without manual ejection and reinsertion. The reuse may include the processor configured to cycle the logical data object through a scratch pool as a selected scratch logical data object and mount the selected scratch logical data object with a write from beginning of tape command to bind at least one data attribute to the WORM data object.

Abstract: A hybrid data storage system is one which has data storage clusters of different types. In a hybrid data storage system, at least one first data storage cluster is configured to store data and has high data storage capacity; and at least one second data storage cluster is configured to store data and has lower data storage capacity than the first cluster. The data is initially replicated and stored by at least one first and at least one second data storage cluster. The method identifies a portion of the stored initially replicated data of at least one second data storage cluster as “pinned”; continues to store the pinned initially replicated data; and selectively removes non-pinned initially replicated data from the second data storage cluster(s) to account for the capacity difference.

Abstract: A data storage system stores logical data object(s), each identified by a logical identifier. A control is configured to assign a unique WORM (Write Once Read Many) identifier to the logical data object, and stores the unique WORM identifier as associated with the logical identifier, in a database maintained by the control so as to be persistent. Data storage is configured to write the logical data object with a header with the unique WORM identifier. The control, in order to allow the logical data object to be accessed externally to the control, requires matching the unique WORM identifier in the header of a logical data object to the unique WORM identifier of the persistent database for the logical object. The unique WORM identifier is formed of a checksum hash value related to nonce fields comprising at least the logical identifier of the logical data object, an incrementing token, and a time stamp.

Abstract: Various method, system, and computer program product embodiments for implementing selective write-protect by a processor in a data storage system within a plurality of redundant storage systems for disaster recovery testing are provided. In one such embodiment, a write-protect state is initiated within at least one of the plurality of redundant storage systems. An available plurality of categories, including at least one write-protect exclusion category, is configured within a management interface of the data storage system, such that during the disaster recovery testing a storage volume categorized in the write-protect exclusion category is excluded from write protection.

Abstract: A method for throttling host throughput in a computer storage subsystem is provided. The host throughput is compared to a throughput limit for a predetermined time period. If the host throughput exceeds the throughput limit during the predetermined time period, an input/output (I/O) delay is set equal to the remainder of the predetermined time period, and the delay is implemented for an associated storage device of the computer storage subsystem.

Abstract: A method for controlling the throughput in a communications channel between a host and its storage subsystem is disclosed. A determination is made whether or not a total throughput value is greater than a predetermined maximum throughput value. If the total throughput value is greater than the predetermined maximum throughput value, a delay is applied to the communications channel. If the total throughput value is not greater than the predetermined maximum throughput value, another determination is made whether or not one time period has completed. If one time period has completed, a total throughput value and an exponential moving average (EMA) throughput value of the communications channel is retrieved, a new EMA throughput value is generated based on the total throughput value and the EMA throughput value, and adjusting the total throughput value based on whether or not the new throughput value is greater than a predetermined maximum throughput value.

Abstract: A method for controlling the throughput in a communications channel between a host and its storage subsystem is disclosed. A determination is made whether or not a total throughput value is greater than a predetermined maximum throughput value. If the total throughput value is greater than the predetermined maximum throughput value, a delay is applied to the communications channel. If the total throughput value is not greater than the predetermined maximum throughput value, another determination is made whether or not one time period has completed. If one time period has completed, a total throughput value and an exponential moving average (EMA) throughput value of the communications channel is retrieved, a new EMA throughput value is generated based on the total throughput value and the EMA throughput value, and adjusting the total throughput value based on whether or not the new throughput value is greater than a predetermined maximum throughput value.

Abstract: A method for throttling host throughput in a computer storage subsystem is provided. The host throughput is compared to a throughput limit for a predetermined time period. If the host throughput exceeds the throughput limit during the predetermined time period, an input/output (I/O) delay is set equal to the remainder of the predetermined time period, and the delay is implemented for an associated storage device of the computer storage subsystem.

Abstract: A composite storage server employs a plurality of distributed storage sites including a mount site, a source copy site and one ore more copy target sites for executing a storage of volume data within the composite storage server. In operation, a deferred copy target site receives a communication of a source copy complete message from the mount site, the source copy complete message being indicative of the source copy site having a complete copy of the volume data, and detects a transition by the mount site of the host job from an active status to an inactive status subsequent to the communication of the source copy complete message from the mount site. Based on the inactive status of the host job, the deferred copy target site pulls the volume data from a peer distributed storage site having a complete copy of the volume data.

Abstract: In a system including an application subsystem node having an application RSID table and a logging subsystem node having a logging RSID table, the application subsystem node makes a determination of a registration status of a ALSI string relative to the application RSID table during a logging operation of the ALSI string. The application subsystem node further transfers a RSID package from the application subsystem node across a network to the logging subsystem node, wherein the RSID package includes a RSID encoding of the ALSI string and conditionally includes the ALSI string based on the registration status of the ALIS string relative to the application RSID table as determined by the application subsystem node.

Abstract: A dynamic selection of a communications link between a storage controller and one of a plurality of storage servers is provided so as to enhance the performance of the storage system. The storage system includes a plurality of storage devices, a corresponding plurality of virtual storage controllers coupled to the storage devices and a virtual storage controller. The virtual storage controller includes a host interface, a server interface, a stored table and a processing unit. The stored table includes a list identifying the active links between the server interface and each virtual storage server and, for each active link, a corresponding performance value.

Abstract: A dynamic selection of a communications link between a storage controller and one of a plurality of storage servers is provided so as to enhance the performance of the storage system. The storage system includes a plurality of storage devices, a corresponding plurality of virtual storage controllers coupled to the storage devices and a virtual storage controller. The virtual storage controller includes a host interface, a server interface, a stored table and a processing unit. The stored table includes a list identifying the active links between the server interface and each virtual storage server and, for each active link, a corresponding performance value.