Abstract: Migrating an active VM from a first data center to a second data center having a passive counterpart of the active VM includes freezing the active VM at the first data center, creating an active VM at the second data center that corresponds to the passive counterpart, and restarting the active VM at the second data center. Migrating an active VM from a first data center to a second data center may also include waiting for the passive counterpart to be synchronized with the active VM at the first data center prior to converting the passive counterpart. Creating the active VM at the second data center may include providing a snapshot of a volume containing the passive VM.

Abstract: Dynamically creating a communication path between first and second storage devices, includes creating a connection to a source volume on the first storage device and indicating that the source volume is not ready to transmit data on the communication path, after successfully creating the connection to the source volume, creating a connection to a destination volume on the second storage device and initially indicating that portions of one of: the destination volume and the source volume do not contain valid copies of data, where the destination volume accepts data from the source volume, and after successfully creating the connections to the source and destination volumes, indicating that the source volume is ready to transmit data on the communication path. Dynamically creating a communication path between first and second storage devices, may also include creating at least one of: the source volume and the destination volume.

Abstract: Handling asynchronous data provided by at least two sources includes receiving a first portion of the data from a first one of the sources, receiving a second portion of the data from a second one of the sources, where the first and second portions provide the same data, and saving at least one of the portions containing more recent data. The sources may be synchronized with each other to contain the same data. All of the portions may be saved. A portion that contains data that is older than the more recent data may be discarded. Handling asynchronous data provided by at least two sources may also include establishing an active leg for data provided by one of the sources, establishing a passive leg for data provided by an other one of the sources, and saving data provided through the active leg.

Abstract: Migrating data from an old storage device to a new storage device includes creating new paths to the new storage device, freezing old paths to the old storage device, transferring metadata corresponding to the old storage device to the new storage device, where state information is transferred from the old storage device to the new storage device, and thawing the new paths. Migrating data from an old storage device to a new storage device may also include creating new volumes on the new storage device and transferring data from the old storage device to the new storage device. Migrating data from an old storage device to a new storage device may also include dismantling the old paths.

Abstract: A method, system, and computer program product for ordering a plurality of data IO captured at a primary site to be applied at a secondary site, comprising removing the one or more extent level portions from the captured data IO, determining if the one or more extent level portions are time sequenced to overwrite a portion of data of the data IO, based on a determination that the portion data is to be overwritten, removing the overwritten portion of data from the plurality of the data IO and ordering the one or more extent level portions to be applied at the secondary site before the captured data IO.

Abstract: Described are techniques for performing dynamic binding of device identifiers to data storage devices. A first device identifier assigned to an application on a host is received. The first device identifier is a unique detachable device identifier dynamically bound to different data storage devices at different points in time in accordance with data storage devices used by the application. The first device identifier is attached to a first data storage device of the data storage system used by the application at a first point in time. The first device identifier is detached from the first data storage device thereby making the first data storage device unavailable for data operations from the application. The first device identifier is attached to a second data storage device used by the application at a second point in time thereby making the second data storage device available for data operations from the application.

Abstract: Sharing at least one link among a plurality of processes includes determining a capacity of the at least one link based on a number of I/O operations per unit time supported by the at least one link as a function of the amount of data provided by each of the I/O operations, determining a requirement of each of the processes based on user specifications and an amount of data provided by each I/O operation for each of the processes, and apportioning link capacity among the processes according to the requirement of each of the processes. In response to a sum of requirements for each of the processes being less than the capacity of the at least one link, additional link capacity may be provided to at least some of the processes.

Abstract: A method for scanning a message-list accessible to a plurality of processors includes retrieving, from a cache associated with a scanning processor from the plurality of processors, information identifying a starting message-slot. This information is then used to begin a scan of the message-list at that starting message-slot. The information indicating the starting message-slot is obtained by identifying, in the message-list, a message-slot containing a message intended for a recipient processor from the plurality of processors and obtaining, from the identified message-slot, information indicative of a location of a succeeding message-slot in the message-list. This information is then cached, for retrieval during a subsequent scan of the message-list.

Abstract: Reversing a communication path between a first volume on a first storage device and a second volume on a second storage device includes suspending communication between the first and second volumes while maintaining operations for other volumes of the storage devices, causing the first volume to change from a source volume to a destination volume without destroying the first volume, causing the second volume to change from a destination volume to a source volume without destroying the second volume, and resuming communication between the first and second volumes. Causing the first volume to change from a source volume to a destination volume may include modifying a table of the first storage device. Causing the second volume to change from a source volume to a destination volume may include modifying a table of the second storage device.

Abstract: Handling asynchronous data provided by at least two sources includes synchronizing data between the at least two sources, coordinating cycle switching between the at least two sources, where an asynchronous cycle of data from one of the sources corresponds to an asynchronous cycle of data from an other one of the sources, receiving asynchronous data corresponding to a data cycle from at least one of the sources, and saving at least some of the received data. A first portion of data for a particular cycle may be transmitted from one of the sources and a second portion of data for the particular cycle, different from the first portion of data, may be transmitted from an other one of the sources and the first portion and the second portion together may correspond to all of the data for the particular cycle.

Abstract: The disclosure relates to a method and system for creating a virtual array in a physical array. Unassigned whole volumes in at least one physical array are identified. The identified volumes are associated with a first virtual array. Unique names are given to the identified volumes. At least one path is assigned to the first virtual array. The first virtual array may be associated with a second virtual array. Data may be migrated or replicated from the first virtual array to the second virtual array using existing array services.

Abstract: Migrating data from an old storage device to a new storage device includes transferring the data from a first logical device on the old storage device to a second logical device on the new storage device, determining replication relationships for the first logical device, transferring the replication relationships; and transferring logical devices used for the replication relationships from the old storage device to the new storage device. The replication relationships may include a clone of the first logical device. Migrating data from an old storage device to a new storage device may also include suspending writes to the first logical storage device prior to transferring the data for the first logical storage device. The replication relationships may include at least one snapshot.

Abstract: A system for managing distributed storage includes a collection of one or more compute sites that are connected and that perform a joint computation. A witness node is connected to the one or more compute sites. A membership service allows a change in collection membership, in response to a failure, to continue the joint computation without causing data inconsistency or corruption. If the membership service is unable to reach a decision on the change in collection membership in response to the failure, the witness node controls the decision on the change in collection membership to continue the joint computation. A distributed storage system provided by the system described herein may advantageously meet consistency guarantees and maximize data access even when individual compute sites and/or their interconnects fail.

Abstract: Migrating data from an old storage device to a new storage device includes creating new paths to the new storage device, freezing old paths to the old storage device, transferring metadata corresponding to the old storage device to the new storage device, where state information is transferred from the old storage device to the new storage device, and thawing the new paths. Migrating data from an old storage device to a new storage device may also include creating new volumes on the new storage device and transferring data from the old storage device to the new storage device. Migrating data from an old storage device to a new storage device may also include dismantling the old paths.

Abstract: An active/active remote mirroring system, for example an active/active SRDF system, provides for remote mirroring between multiple storage volumes, e.g., a first storage device and a second storage device, in which the storage devices may both be active. A plurality of hosts may be coupled to either the first storage device, the second storage device, or both to conduct read and write operations from and to the storage devices, for example to nearest device. The hosts may be part of an application cluster. The first storage device and the second storage device may be connected via a link, such as an SRDF link, for providing remote mirroring capabilities between the storage volumes. In various embodiments the first and second storage devices may be separate devices, volumes, or portions thereof, and/or may be different portions of the same storage device.

Abstract: A system for controlling the pacing of host data writes in response to changing system conditions allows for the use of variably controlled delays that facilitate asynchronous replication with bounded lag and smooth steady-state performance. Adding delay to the writes slows down the host and dampens activity spikes. A first storage device receives a write request, transmits data to a second storage device, and acknowledges the write request. An amount of additional write response time is controlled between when the write request is received and when the write request is acknowledged by the first storage device, where the amount of additional write response time is controlled according to system parameters including an amount of lag time between when the write request is received and when the write request is committed at the second storage device.

Abstract: Providing multiple jobs for a device associated with a communication device includes providing a plurality of device records, where each of the device records corresponds to a device associated with the communication device, providing a plurality of job records for at least one of the device records, where each of the job records contains at least some information that is also provided in the corresponding one of the device records, and linking the job records and the corresponding device record so that any one of the job records may be accessed by first accessing the corresponding one of the device records. Providing multiple jobs may also include providing one of a plurality of shared pointers in each of the job records and the corresponding one of the device records, where all of the shared pointers point to the corresponding one of the device records. Linking the job records may include providing a forward pointer and a backward pointer for each of the job records.

Abstract: Dynamically creating a communication path between first and second storage devices, includes creating a connection to a source volume on the first storage device and indicating that the source volume is not ready to transmit data on the communication path, after successfully creating the connection to the source volume, creating a connection to a destination volume on the second storage device and initially indicating that portions of one of: the destination volume and the source volume do not contain valid copies of data, where the destination volume accepts data from the source volume, and after successfully creating the connections to the source and destination volumes, indicating that the source volume is ready to transmit data on the communication path. Dynamically creating a communication path between first and second storage devices, may also include creating at least one of: the source volume and the destination volume.

Abstract: A mechanism to support remote mirroring of storage devices by data storage systems in a one-to-many switched environment. Each data storage system includes a disk director that is adapted to control at least one device group that is supported in a mirrored configuration with a corresponding device group controlled by one of the other data storage systems. For each device group and corresponding device group, there are first ports associated with the device group and second ports associated with the corresponding device group. A switch element is adapted to connect one of the first ports to at least one of the second ports so that data may be exchanged between the ports for each device group and corresponding device group. The disk director selects which first port is to be connected to which second port via the switch element in the establishment of a logical link.

Abstract: A mechanism to support remote mirroring of storage devices by data storage systems in a one-to-many switched environment. Each data storage system includes a disk director that is adapted to control at least one device group that is supported in a mirrored configuration with a corresponding device group controlled by one of the other data storage systems. For each device group and corresponding device group, there are first ports associated with the device group and second ports associated with the corresponding device group. A switch element is adapted to connect one of the first ports to at least one of the second ports so that data may be exchanged between the ports for each device group and corresponding device group. The disk director selects which first port is to be connected to which second port via the switch element in the establishment of a logical link.