Abstract: Techniques are described for copying data. At a first storage processor, a copy request is received to copy data including copying source data from a source area of a source logical device to a destination area of a destination logical device. The source logical device is owned by the first storage processor and the destination logical device is owned by a second storage processor. The first storage processor receives, from the second storage processor, destination location physical storage mapping information for the destination area. A destination physical device location corresponding to the destination area is determined. The source data from the source area is stored in a first cache location of a first data cache of the first storage processor. The first cache location is modified to indicate it includes write pending data for the destination physical device location. The source data is destaged to the destination physical device location.

Abstract: There are disclosed techniques for use in managing data copying. In one embodiment, there is disclosed a method including a number of steps. The method comprises performing a first operation to copy data from a first region of a source area. The method also comprises determining a count relating to pending I/O requests in connection with a second region of the source area upon completion of the first operation. And, in response to determining that the count relating to pending I/O requests in connection with the second region of the source area equals zero, the method further comprises performing a second operation to copy data from the second region of the source area and configuring a new region in the source area to record a count relating to pending I/O requests in connection with the source area.

Abstract: A technique for managing copy sessions in a data storage system supports active and inactive copy-session states and reclaims memory for inactive copy sessions to reduce their memory footprints. When a copy session transitions from the active state to the inactive state, the copy session persists certain copy-progress data in non-volatile storage and frees structures in memory previously storing that copy-progress data. The inactive copy session continues to run but performs no copying and consumes less memory. When the copy session later transitions back to the active state, the copy session reads the copy-progress data back into memory and resumes copying.

Abstract: A copy technique involves generating, upon receiving a command to copy at least a portion of a source file, a set of pointers for a destination file that point to a set of pointers for the source file (“physical block pointers”), which in turn point to physical blocks storing data of the file in a storage system. In response to the copy command, a storage processor allocates an inode from an inode table of a file system for the destination file and stores a set of inode pointers in the inode of the destination file that point to the set of pointers for the source file. Thus, instead of creating a redundant copy of the data of the source file, the improved creates technique creates pointers that point to the data stored for the source file.

Abstract: The subject disclosure is generally directed towards load balancing between storage processors based upon dynamic redirection statistics, in which load balancing includes changing a preferred path/a mounted file system from one storage processor to another. In one example, load balancing technology compares a current delta of directed and redirected I/O counts to a previous delta. If the result turns from negative to positive, that is, redirection is becoming prevalent, a load balancing threshold may be changed based upon the current delta value. Load balancing is thus based on the latest trend of I/O redirection.

Abstract: A method is used in managing accesses to storage. An amount of data storage space in use by a mapped logical volume and RAID group characteristics of a storage pool used by the mapped logical volume are determined. Based on the amount and the RAID group characteristics, a report of storage resources corresponding to the mapped logical volume is produced. Based on the report, accesses to the mapped logical volume are controlled.

Abstract: Techniques for processing requests are described. A first thread is selected for execution. Only a single thread is allowed to execute at a time. Each thread is associated with a queue of requests to be processed by the thread. A first request is selected from the queue of first thread that performs first processing to service the first request. A service time classification for the first request is determined in accordance with criteria that includes a runtime determination of what resource(s) are used in servicing the first request. It is determined, in accordance with the service time classification, whether to allow the first thread to continue execution and process a second request from the queue of the first thread. If the first thread is allowed to continue execution, second processing is performed by the first thread to service the second request. Otherwise, a second thread is selected for execution.

Abstract: An improved technique involves managing conflicts over data changes between a data change initiator and multiple listeners to allow any of the listeners to prevent the initiator from changing data. Along these lines, a data change notification process resides in a storage processor in memory outside of an I/O stack in which the listeners and data change initiators reside. When a data change initiator prepares to perform a data change operation, it notifies the data change notification process. The data change notification process in turn sends a notification to the listeners that have registered with the data change notification process. If there is a peer data change notification process on another storage processor, the data change notification process sends a notification to that peer data change notification process so that the peer data change notification process may notify its registered listeners.

Abstract: Techniques for memory management are described. A memory management data structure may include a tree structure of nodes each representing a free memory portion of a size used as a key value. The tree may be a modified AVL tree with nodes sorted based on key values corresponding to free memory portion sizes. The data structure may include a first list representing a memory map corresponding to different memory portions where each entry of the first list represents a memory portion with an associated memory address range that is not contiguous with respect to any other memory address range of any other memory portion represented by an entry on the first list. Each entry of the first list representing a free memory portion may be associated with a node of the tree structure.

Abstract: Techniques are described for performing a copy operation. A first request is received to perform a copy operation. The first request includes a set of parameters in accordance with a defined interface and include a source area and a target area. The source area includes source ranges and source devices. Each of the source ranges identifies a portion of a logical address range of a different one of the source devices. The target area includes target ranges and target devices. Each of the target ranges identifies a portion of a logical address range of a different one of the target devices. The first request is partitioned in to a plurality of other requests each of which is a request to copy a portion of source data located in the source area to a corresponding location in the target area. The other requests are then issued.

Abstract: Techniques are described for generating a unique identifier by a first processor using a plurality of values including a shared value, the first processor's identifier, a container identifier and a time value. The shared value is a common value used by a plurality of processors including the first processor. The container identifier identifies a memory location. The time value denotes an amount of time that has elapsed since the first processor was last booted.

Abstract: Techniques for creating logical units associated with a data storage system. In one example, a method comprises the following steps. One or more blocks of source data associated with a data storage system are identified. The one or more blocks of source data are associated with at least a first logical unit that exists in the data storage system. A second logical unit is created which references the one or more identified blocks of source data.

Abstract: A technique manages peer messaging across multiple SPs of a data storage array. The technique involves using a token, by a first SP of the data storage array, to identify particular data stored at a source storage location on the data storage array. The technique further involves starting, by the first SP, multiple WUT operations which use the token in response to multiple WUT requests, each WUT operation moving the particular data from the source storage location to a respective destination storage location. The technique further involves providing, by the first SP, a single “touch” message in response to starting the multiple WUT operations by the first SP, the single “touch” message informing a set of other SPs of the data storage array that the token which identifies the particular data has been touched.

Abstract: A technique manages token states across multiple storage processors (SPs) of a data storage array. The technique involves using a token, by a first SP, to identify particular data stored on the array. The technique further involves updating, by the first SP, a first SP-controlled set of token state information for the token, the first SP-controlled set of token state information including (i) a first token state which indicates whether the token is “idle” or “busy” from a perspective of the first SP and (ii) a second token state which indicates whether the token is “idle” or “busy” from a perspective of a second SP. The technique further involves expiring, by the first SP, the token in response to the first SP-controlled set of token state information indicating that the token has remained “idle” for at least a predefined amount of time.

Abstract: A method, computer program product, and computing system for receiving, on a first storage processor, a configuration IO request concerning a data array coupled to the first storage processor. The configuration IO request is provided to the data array for execution. A failure indication that the configuration IO request failed to execute is received. In response to receiving the failure indication, a status indicator is determined for a second storage processor coupled to the data array. Whether to reset the first storage processor is determined based, at least in part, upon the status indicator of the second storage processor.

Abstract: Techniques are described for generating a unique identifier by a first processor using a plurality of values including a shared value, the first processor's identifier, a container identifier and a time value. The shared value is a common value used by a plurality of processors including the first processor. The container identifier identifies a memory location. The time value denotes an amount of time that has elapsed since the first processor was last booted.

Abstract: A method, computer program product, and computing system for identifying a target storage device upon which a plurality of logical storage devices are to be defined. The target storage device includes a plurality of physical storage blocks. At least a first logical storage device and a second logical storage device are defined for mapping within the target storage device. Each of the first and second logical storage devices includes a plurality of logical storage slices. At least a portion of the logical storage slices for each of the first and second logical storage devices are non-sequentially mapped to at least a portion of the plurality of physical storage blocks included within the target storage device to generate an interlaced target storage device.

Abstract: A method is used in managing restore operations in storage systems. A state of a logical object is retrieved and a second logical object is placed in a pre-step mode. An instantaneous restore operation between the first logical object and the second logical object is performed. Drivers that are associated with the instantaneous restore and utilize data-less writes are identified. A granularity value representative of a size at which the identified driver tracks changes is determined. Changed data extents in the first logical object are identified. Data-less writes are sent at the lowest determined granularity to any identified extents in the first logical object.

Abstract: A method is used in managing restore operations in storage systems. A state of a logical object is retrieved and a second logical object is placed in a pre-step mode. An instantaneous restore operation between the first logical object and the second logical object is performed. Changed data extents in the first logical object are identified. Data-less writes are sent to any identified extents in the first logical object.

Abstract: A method is used in managing accesses to storage objects. Access I/Os being directed to at least one storage object are received into a first queue that operates on a first in first out basis. In accordance with the first in first out basis, a batch of the access I/Os is created from the first queue. The batch is transferred to a second queue that is controlled by ordering logic. The batch in the second queue is ordered in accordance with the ordering logic. All of the access I/Os from the second queue are processed in order, before any additional access I/Os are added to the second queue.