Abstract: Example embodiments of the present invention provide for parallel replication of an IO received by a storage array. Such parallelism provide numerous benefits, including enqueuing the command phase of the write command at the storage array and the replication appliance in parallel, providing data still in memory (i.e., slot) and not destaged to disk, and providing data processing in parallel (e.g., validate checksum, validate data is good, validate internal data structures).

Abstract: A system having a plurality of directors, at least some of which have a local director memory, accesses requested data by determining if requested data is in local director memory of a first one of the directors in response to an access request for the requested data by the first one of the directors. The system also determines if the requested data is native to the first one of the directors in response to the requested data not being in the local director memory of the first one of the directors, where data provided on a physical storage device coupled to the first one of the directors is native to the first one of the directors. The system also obtains the requested data from a second one of the directors in response to the requested data not being native to the first one of the directors.

Abstract: Controlling I/O operations with a storage device includes establishing a quota that corresponds to a maximum amount of data to store on the storage device in a given amount of time, determining if processing an I/O operation would cause the quota to be exceeded, and performing the I/O operation if the quota is not exceeded. The quota may be provided in I/O operations per second or as I/O throughput. Controlling I/O operations with a storage device may also include accumulating credit in response to a rate of I/O operations being less than the quota and performing I/O operations when the quota is exceeded in response to the credit being greater than zero. The credit may be decreased if an I/O operation is performed when the quota is exceeded.

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: Global memory of a storage system may be used to provide NVRAM capabilities to guest operating systems accessing the storage system. The non-volatility of NVRAM (i.e. that retains its information when power is turned off) provides that an NVRAM device provided by global memory may be used as a journaling device to track storage operations and facilitate recovery and/or failover processing in a storage system without needing to add additional hardware and/or other installed devices. Use of the global memory according to the system described herein to provide an NVRAM device, that may function as a journaling device, provides for the speeding up of transactions, thereby improving metadata intensive operations performance and reducing recovery time and/or failover time of a storage system without adding additional hardware support.

Abstract: Controlling I/O operations with a storage device includes establishing a quota that corresponds to a maximum amount of data to store on the storage device in a given amount of time, determining if processing an I/O operation would cause the quota to be exceeded, and performing the I/O operation if the quota is not exceeded. The quota may be provided in I/O operations per second or as I/O throughput. Controlling I/O operations with a storage device may also include accumulating credit in response to a rate of I/O operations being less than the quota and performing I/O operations when the quota is exceeded in response to the credit being greater than zero. The credit may be decreased if an I/O operation is performed when the quota is exceeded.

Abstract: Described are techniques for performing path selection. A data operation is received for a metadevice comprising a plurality of metadevice members. A first of the plurality of metadevice members is determined. The first member is the member to which the data operation is directed. In accordance with a load balancing technique for the first metadevice member, path selection is performed to select a first of a plurality of paths. The metadevice is accessible over each of the plurality of paths. The data operation is sent over the first path.

Abstract: Described are techniques for performing processing in a data storage system. A client application executing on a host is identified as a candidate for migration to the data storage system. First data used by the client application is stored on one or more physical storage devices of the data storage system. The client application is migrated to the data storage system for temporary execution on the data storage system. The client application is executed on the data storage system for a time period using a first portion of resources of the data storage system allocated for exclusive use by migrated client applications executing on the data storage system.

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: 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: Described are techniques for allocating resources. Two consumer processes using two resources are provided. A first threshold of a first of the resources for a first of said two consumer processes is provided. A second threshold of a second of said resources for said first consumer process is provided. Consumption information is received regarding actual consumption of the two resources by the first consumer process. Execution of the first consumer process is scheduled in accordance with the first and the second thresholds and the consumption information.

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: Described are techniques for determining preferred paths. A host requests first information from each of one or more ports of a data storage system. The first information includes preferred path information for a first device visible to the host through each port. The preferred path information includes one or more parameters used by said host to perform one or more mathematical calculations to determine a preferred path for transmitting to the data storage system a data operation directed to the first device. The first information is sent from each port to the host.

Abstract: Described are techniques for servicing data requests in a data storage system. One or more data requests from an application executing on the host are received. The data storage system allocates a first amount of resources for use in servicing data requests from the application. Behavior of the host is monitored for occurrences of I/O failure. In accordance with criteria and the occurrences of I/O failure, it is determined whether at least one of the host or the application is in a state of pending failure. If it is determined that at least one of the host or the application is in a state of pending failure, a second amount of resources larger than the first amount are allocated for a time period when servicing data requests from the application. After the time period, data requests from the application are serviced in accordance with the first amount of resources.

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 storage configuration. Defined are one or more initiator groups each including one or more initiator ports, one or more target groups each including one or more target ports, and one or more storage groups each including one or more devices. A masking view is created where the masking view includes a first of the initiator groups, a first of the target groups, and a first of the storage groups. The masking view indicates which devices of the first storage group are accessible using one or more paths. Each of the one or more paths is specified using an initiator port from the first initiator group and a target port from the first target group.

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 performing path selection. A data operation is received for a metadevice comprising a plurality of metadevice members. A first of the plurality of metadevice members is determined. The first member is the member to which the data operation is directed. In accordance with a load balancing technique for the first metadevice member, path selection is performed to select a first of a plurality of paths. The metadevice is accessible over each of the plurality of paths. The data operation is sent over the first path.

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: 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.