Abstract: Techniques are provided for a computer device to receive and store data comprising information configured to indicate boot device parameters for devices to be initialized during a given boot sequence. Those devices that match the device parameters are initialized prior to loading the computer device's operating system. Devices that do not match the boot parameters are masked out by the BIOS, and Option ROM firmware is loaded and executed for those devices that match the boot parameters.

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: Techniques for reducing data storage needs using continuous data protection and replication are disclosed. In one particular exemplary embodiment, the techniques may be realized as a method for reducing data storage needs using a continuous data protection and replication device comprising creating a master image of material identified by a user, generating a virtual replica of the master image on a storage area network using the continuous data protection and replication device to virtualize physical storage containing the master image, generating a copy of the virtual replica on the storage area network, and providing a virtual logical unit number to access the copy, wherein the access enables a process which requires exclusive access to content of the master image to obtain such access without requiring physical storage for an entire copy of the master image.

Abstract: An apparatus and method for faster recovery of validated continuous data protection time images. In one embodiment of the method, an image validation process is initiated. In response, a first write transaction is generated for writing first new data to a first image of a data object that existed at prior time T1. The first new data is written to a first storage. Thereafter data contents of the first storage are copied to a first memory object. Finally, the first memory object is linked with the first image.

Abstract: Redirecting a data object such as a file block extent. The data object can be redirected from a first memory block to a second memory block, wherein the second memory block includes a copy of modified data of the first memory block. The redirection may occur in response to a request to modify data of the data object. Redirection preserves the prior version of the data object stored in the first memory block to enable restoration of the data object if needed. In one embodiment, a first data object is mapped to a first memory block. A copy of data contents of the first memory block is created. Thereafter, data contained within the copy is modified in accordance, for example, with a request to write data to the first data object. The modified copy is stored in a second memory block, and the first data object is mapped to the second memory block.

Abstract: A method involves detecting that a first storage device is inaccessible. The information stored on the first storage device is a synchronized copy of information stored on a second storage device. In response to detecting that the first storage device is inaccessible, modification logging is initiated. Modification logging involves detecting modifications to information stored on the second storage device and storing information that indicates an order in which the modifications occur to the second storage device. The stored information can indicate the order explicitly (e.g., by including a timestamp or sequence number) or indirectly (e.g., the order of entries stored in a log can indicate the order of the modifications represented by those entries). The stored information can also include the new values generated by the modifications. The stored information can then be used to resynchronize the information stored on the first and second storage devices.

Abstract: A method for inserting a validated time-image on a primary CDP subsystem in a continuous data protection and replication (CDP/R) subsystem. In one embodiment, the method includes processing data of RI1 at a secondary system in accordance with a recovery process, wherein RI1 is a first image of a replication of a data object. First data is generated in response to processing the data of RI1 in accordance with the recovery process, wherein the first data relates to processing the data of RI1 in accordance with the recovery process. Once the first data is generated, a copy of the first data is transmitted to a primary system that stores the data object.

Abstract: A system or method for reestablishing data consistency between data volume P and its real time or near real time copy volume S. When volumes P and S enter a state of data inconsistency, data consistency can be restored through use of roll-back and/or roll-forward logs. The roll-forward log stores new data to be written to volume P. The roll-back log stores existing data of volume S before the existing data of volume S is overwritten with new data. As will be more fully described below, the roll-back log can be used to incrementally restore volume S to a prior data state in reverse chronological order, while a roll-forward log can be used to incrementally restore volume S in forward chronological to equal the data state of volume P.

Abstract: Various systems and methods are disclosed for applying incremental changes prior to initialization of a point-in-time copy. For example, one method involves identifying an incremental change to information stored on a primary device. The incremental change is identified subsequent to a first point in time. The incremental change is applied to a first target device, prior to completing initialization of a second target device. The initialization of the second target device initializes the second target device as a point-in-time copy of the primary device. The point-in-time copy of the primary device is a copy of the primary device at the first point in time.

Abstract: A method includes assigning a port identifier to a first port on a node and communicating data on a first path between the first port and a logical unit on an active/passive storage array. The port identifier is registered in a persistent reservation scheme for the logical unit. The method also includes detecting a failure of the first path, de-assigning the port identifier from the first port, assigning the port identifier to a second port on the first node, and resuming communications between the node and the logical unit. One implementation of a system includes a first port configured to communicate with a storage device, a second port configured to communicate with the storage device, and an identifier management block. The identifier management block executes a failover with N_Port ID Virtualization commands that transfer a world wide port name from the first port to the second port.

Abstract: A technique for disaster rehearsal testing in storage area network (SAN) utilizing a replication appliance is disclosed. In one particular exemplary embodiment, the technique may be realized as a method for disaster rehearsal testing of a secondary storage area network utilizing a replication appliance comprising the steps of stopping data writes to one or more logical unit numbers associated with the secondary storage area network, accumulating the data writes from a primary storage area network in one or more journals associated with the secondary storage area network, redirecting one or more data input/output requests, wherein data writes generated by testing of the secondary storage area network are redirected to replication appliance associated with the secondary storage area network and read requests for data written by test data writes are redirected to the replication appliance and testing the secondary storage area network.

Abstract: A system or method for creating a point-in-time (PIT) or backup copy of one or more data volumes using a roll-back log. The backup copy can be created without employing hot backup mode. In one embodiment, the method includes copying data blocks of a volume to a backup memory configured to store a backup copy of the volume, wherein the data blocks are sequentially copied until all of the data blocks of the volume are copied to the backup memory. A first request is generated to overwrite existing data of a first data block of the volume with new data before all of the data blocks of the volume are copied to the backup memory. Before overwriting the existing data and before all of the data blocks of the volume are copied to the backup memory, the existing data is copied to a first memory (e.g., the roll-back log). Before all of the data blocks of the volume are copied to the backup memory, the existing data is overwritten with the new data.

Abstract: One method of updating a change track map involves resetting a mirror recovery map for a data volume. Just before the mirror recovery map is reset, a change track map for the data volume can be updated, using the mirror recovery map. The mirror recovery map can be reset by a data element of a data processing system, while the change track map can be updated by a control element of the data processing system.

Abstract: Various methods and systems are disclosed for handling I/O requests to a replica that has not yet been fully synchronized. One method involves detecting the transfer of the role of working volume from a first volume to a second volume. The second volume is configured as a replica of the first volume, but the second volume may not be fully synchronized with the first volume at the time that the role of working volume is transferred. Subsequent to the role of working volume being transferred to the second volume, a read request to the second volume is satisfied by accessing a log. The log is configured to store values that have been written to the first volume, and at least one of the values written to the first volume has not been written to the second volume.

Abstract: System and method for resynchronizing mirrored volumes in a storage system. According to one embodiment, a system may include a first volume located at a primary site and associated with a first storage management device, and a second volume located at a secondary site and associated with a second storage management device, where the secondary site is coupled to the primary site via a data link, and where the second volume is configured as a mirror of the first volume. The first storage management device may be configured to convey to the second storage management device an indication of a data block written to the first volume subsequent to a failure of the data link. Dependent upon the indication, the second storage management device may be configured to create a snapshot of the data block as stored on the second volume prior to resynchronization of the data block.

Abstract: A system for volume replication in a distributed block virtualization environment includes a first and a second set of one or more physical block devices, a first and a second volume server, one or more volume clients, and a replication manager. The first volume server may be configured to aggregate storage in the first set of one or more physical block devices into one or more logical volumes, and to make the one or more logical volumes accessible to the one or more volume clients. The replication manager may be configured to operate in cooperation with the first and second volume servers and the one or more volume clients to maintain a replica of at least a subset of the one or more logical volumes at the second set of one or more physical block devices.

Abstract: An apparatus and method for faster recovery of validated continuous data protection time images. In one embodiment of the method, an image validation process is initiated. In response, a first write transaction is generated for writing first new data to a first image of a data object that existed at prior time T1. The first new data is written to a first storage. Thereafter data contents of the first storage are copied to a first memory object. Finally, the first memory object is linked with the first image.

Abstract: A roll-back memory can be used to incrementally restore one or more data volumes in reverse chronological order to the data state they occupied at some prior point in time without using a backup copy. After the one or more data volumes have been restored in reverse chronological order, a roll-forward memory can be used to incrementally restore the one or more data volumes in forward chronological order to the data state they occupied at some other point in time without using a backup copy. Incrementally restoring the one or more data volumes in reverse chronological order may follow an incremental restoration of the one or more data volumes in forward chronological order and vice versa until the one or more data volumes are in the data state they occupied just prior to, for example, a data corruption event.

Abstract: One goal of consistency interval replication is to achieve a consistent copy of data generated by independent streams of writes from nodes in a clustered/distributed environment. Two writes to the same block from different nodes may arrive at a replication target in a different order from the order in which they were written to primary storage. A consistency interval coordinator may analyze a list of blocks modified during a consistency interval to determine conflict blocks written to by two different nodes during the same consistency interval. Conflict resolution may involve a node reading data for a conflict block from primary storage and forwarding it to the replication target or a node completing a suspended in-progress write for the conflict block. Once the conflicts have been resolved, the replication target may checkpoint the data modified during the interval and nodes may resume writes to the conflict blocks for the new interval.

Abstract: A method, system, computer system, and computer-readable medium that identify the number of times areas of storage are updated and use that information to synchronize primary and secondary storage areas. The invention enables quick resumption of operations upon a discovery that primary and secondary data have become unsynchronized. Regions of storage that are unsynchronized can be identified quickly without the need to read the change log. In addition, data are copied efficiently, with minimal or no duplication of effort or data. Faster and more reliable storage can be allocated for storing regions of data that are “hot spots,” thereby making better use of existing storage resources and budgets.