Abstract: Described are techniques for migrating data from a source device of a source data storage system to a target device of a target data storage system. The target data storage system is configured to operate in accordance with a spoofing mode and a pass-through mode. A first set of commands from the host are processed for the target device when in the pass-through mode and the spoofing mode with respect to the target device. Data is migrated from the source device to the target device. The target data storage system is configured to operate in an echo mode for the target device and processes a second set of commands from the host when in the echo mode for the target device using information stored in the cache from processing the first set of commands.

Abstract: A technique automatically handles a failure during online data migration from a source array to a target array. While a host initially accesses data from the source array using multipath I/O software, the technique involves (i) transitioning the source array to a passive mode, and the target array to an active mode, and (ii) beginning a data transfer operation which transfers data from the source array to the target array. The technique further involves modifying the data on both the target array and the source array in response to modification commands sent to the target array from the host while the data transfer operation is ongoing. The technique further involves automatically failing back to providing access to the data from the source array in response to an event in which the target array loses communication with the source array for a predefined amount of time.

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 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: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: A technique automatically handles a failure during online data migration from a source array to a target array. While a host initially accesses data from the source array using multipath I/O software, the technique involves (i) transitioning the source array to a passive mode, and the target array to an active mode, and (ii) beginning a data transfer operation which transfers data from the source array to the target array. The technique further involves modifying the data on both the target array and the source array in response to modification commands sent to the target array from the host while the data transfer operation is ongoing. The technique further involves automatically failing back to providing access to the data from the source array in response to an event in which the target array loses communication with the source array for a predefined amount of time.

Abstract: A technique migrates data from source arrays to target arrays. The array devices operate in either active mode, passive mode, or stalled-active mode. The technique involves providing active-to-passive instructions to transition the source devices from active to passive while a host initially accesses host data from the source arrays using MPIO software (the target devices being in stalled-active mode), and monitoring whether the source devices successfully transition to passive during a predefined time period. If so, the technique involves operating the target devices in active mode and transferring data from the source devices to the target devices to enable the host to access the host data from the target arrays using the MPIO software. However, if a source device remains passive, the technique involves providing passive-to-active instructions to transition the source devices back to active to enable the host to access the host data from the source arrays.

Abstract: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: A technique migrates data from a source array to a target array while preserving SCSI reservation compliance. The technique involves providing an active-to-passive instruction to the source array while a first SCSI reservation enables hosts to access data on the source array using MPIO software. The active-to-passive instruction directs the source array to transition devices from active mode to passive mode and, upon receipt of a next SCSI instruction, output an indicator indicating that the first SCSI reservation has been cleared. The technique further involves transitioning devices of the target array from passive mode to active mode and beginning a data transfer operation which transfers data from the source array to the target array. The technique further involves automatically effectuating formation of a second SCSI reservation in place of the first SCSI reservation, the second SCSI reservation providing host access to the data on the target array using MPIO software.

Abstract: Described are techniques for verifying host path detection. First information from a first data storage system is received indicating a first set of one or more hosts and, for each host in the first set, which one or more devices of a first device set of the first data storage system are accessible to said each host in the first set over one or more associated paths to the first data storage system. Second information and the first information are received at a second data storage system. First processing is performed at the second data system to determine whether each host included in the first information has successfully completed path detection with respect to a second device set for the second data storage system.

Abstract: Described are techniques for indicating a state associated with a device. A request is received over a path for information about a device. A response to the request is sent. The response indicates a state regarding the device on the path. The response has a response status of good and a payload of a varying size. The payload is truncated at a location prior to that at which a device identifier for the device is expected. In accordance with the response, a state regarding the device on the path is determined.

Abstract: On-line storage devices are migrated to new storage devices in a non-disruptive manner. A host executing multipath I/O software is initially coupled to a source storage device via at least one active path. The target storage device is configured with the source device's device identification information. The target storage device is coupled to the host via a passive path so that the target storage device can return its device identification information to the host but cannot respond to I/O read or I/O write requests from the host. All paths between the host and the source storage device are then disconnected. An on-line data migration session between the source storage device and the target storage device is then activated. The path between the target storage device and the host is then re-configured from passive to active so that the target storage device can respond to I/O read and I/O write requests.

Abstract: A system creates a storage area network (SAN) centric storage virtualization layer in front of storage devices. The system allows data mobility and migration without disruption to the one or more host servers attached to the SAN. Specifically, the host servers are not disrupted when switching I/Os between physical and virtual storage, for example, by taking advantage of WWPN spoofing and Fibre Channel VSAN technology. The use of VSANs effectively allow multiple virtual directors and/or switches to be created within a physical director and/or switches, each with their own separate name server, thereby providing complete isolation from one another. The host-storage pathing information is unchanged as the original physical storage port's WWPNs are spoofed by the virtual storage port. The result is two identical WWPNs within the SAN which is normally disallowed; however, by separating the physical port WWPN into one VSAN and the virtual port WWPN into another, the restriction may be circumvented.

Abstract: Transferring I/O from a first storage device coupled to a storage area network to a second storage device coupled to the storage area network includes blocking I/O operations for a first port of the first storage device coupled to the storage area network, where the first port is associated with an identifier, coupling the second storage device to the storage area network via a port associated with the identifier and reestablishing a connection between the host and the first port to cause I/O operations by the host to be routed to the second storage device. Transferring may also include, following blocking I/O operations for the first port of the first storage device, coupling a second port of the first storage device to the storage area network and migrating data from the first storage device to the second storage device through the second port of the first storage device without host/application disruption.

Abstract: Transferring I/O from a first storage device coupled to a storage area network to a second storage device coupled to the storage area network includes blocking I/O operations for a first port of the first storage device coupled to the storage area network, where the first port is associated with a first identifier. Transferring I/O also includes coupling the second storage device to the storage area network via a port associated with a second identifier different from the first identifier, coupling a virtualization engine to the storage area network via a first port provided with the first identifier and via a second port, and causing at least a portion of I/O operations received by the virtualization engine through the first port thereof to be routed through the second port thereof to the second storage device without host/application disruption.