Abstract: In some examples, a system tracks, in tracking information stored by the system, additions and deletions of objects in a plurality of object stores that are associated with respective control interfaces that control access of the objects in the plurality of object stores, the tracking information identifying a respective object store in which a respective object is stored, and a replication policy for the respective object, the replication policy defining how the respective object is replicated across the plurality of object stores. The system receives, from the control interfaces, indications of additions or deletions of objects in the plurality of object stores, and updates, at the system, the tracking information in response to the received indications.

Abstract: In some examples, a system applies an inline detection of a write of data in a storage, the inline detection to detect potential data encryption of the data. In response to an indication of the potential data encryption, the system creates a first object that represents a first version of the data, and applies a further analysis to determine whether the potential data encryption constitutes unauthorized data encryption, the further analysis based on the first object and a second object that represents a second version of the data that is prior to the first version of the data.

Abstract: In some examples, a system transfers, in a first transfer operation, data of a first storage volume of a first storage location to a second storage volume for a second storage location. Responsive to a completion of the transfer of data of the first storage volume to the second storage volume, the system activates tracking information to track changes to data portions of the second storage volume, the tracking information comprising a plurality of indicators that map to respective different data portions of the second storage volume. As part of a second transfer operation following the first transfer operation, the system transfers changed data indicated by the tracking information from the second storage volume to the first storage volume, without transferring unchanged data in the second storage volume to the first storage volume.

Abstract: In some examples, for migrating data from a first storage system to a second storage system, a system creates a proxy at the first storage system to direct write requests received at the first storage system to the second storage system, initially sets a cache in the first storage system to a first state in which the cache stores write data for first write requests, and changes a state of the cache from the first state to a second state in which write data for second write requests bypasses the cache and are directed by the proxy to the second storage system.

Abstract: In some examples, a system detects recovery, from an unavailable state, of a communication link between a first storage system that includes a first storage volume and a second storage system that includes a second storage volume that is to be a synchronized version of the first storage volume, where while the communication link is in the unavailable state the second storage volume is in an offline state and the first storage volume is in an online state.

Abstract: In some examples, a system detects recovery, from an unavailable state, of a communication link between a first storage system that includes a first storage volume and a second storage system that includes a second storage volume that is to be a synchronized version of the first storage volume, where while the communication link is in the unavailable state the second storage volume is in an offline state and the first storage volume is in an online state.

Abstract: Methods, systems, and computer readable media for performing page fault handling are disclosed. According to one method, the method includes: after a translation lookaside buffer (TLB) miss associated with a virtual memory page occurs, identifying, in a page table, a page table entry (PTE) associated with the virtual memory page; determining, using a first indicator in the PTE, that the virtual memory page is not present in a main memory; determining, using a second indicator in the PTE, that the virtual memory page is associated with a valid memory address and that the virtual memory page is capable of using pre-allocated pages; obtaining, from a pre-allocation table, a page frame number associated with a pre-allocated page; and updating the PTE to indicate the page frame number.

Abstract: In some examples, for migrating data from a first storage system to a second storage system, a system creates a proxy at the first storage system to direct write requests received at the first storage system to the second storage system, initially sets a cache in the first storage system to a first state in which the cache stores write data for first write requests, and changes a state of the cache from the first state to a second state in which write data for second write requests bypasses the cache and are directed by the proxy to the second storage system.

Abstract: In some examples, a system transfers, in a first transfer operation, data of a first storage volume of a first storage location to a second storage volume for a second storage location. Responsive to a completion of the transfer of data of the first storage volume to the second storage volume, the system activates tracking information to track changes to data portions of the second storage volume, the tracking information comprising a plurality of indicators that map to respective different data portions of the second storage volume. As part of a second transfer operation following the first transfer operation, the system transfers changed data indicated by the tracking information from the second storage volume to the first storage volume, without transferring unchanged data in the second storage volume to the first storage volume.

Abstract: Methods, systems, and computer readable media for performing page fault handling are disclosed. According to one method, the method includes: after a translation lookaside buffer (TLB) miss associated with a virtual memory page occurs, identifying, in a page table, a page table entry (PTE) associated with the virtual memory page; determining, using a first indicator in the PTE, that the virtual memory page is not present in a main memory; determining, using a second indicator in the PTE, that the virtual memory page is associated with a valid memory address and that the virtual memory page is capable of using pre-allocated pages; obtaining, from a pre-allocation table, a page frame number associated with a pre-allocated page; and updating the PTE to indicate the page frame number.

Abstract: Examples include compressed extent versions. Examples may create an empty target virtual volume tree having a tree structure of a source virtual volume tree of a source storage system, the source virtual volume tree comprising source base and source snapshot virtual volumes, each representing respective versions of a plurality of extents, wherein each of the extents corresponds to a different portion of an address space of the source base virtual volume. Examples may include compressed extent collections, each comprising a compressed representation of multiple populated versions of a single extent from the source base and snapshot virtual volumes, the multiple populated versions compressed relative to one another.

Abstract: Examples include compressed extent versions. Examples may create an empty target virtual volume tree having a tree structure of a source virtual volume tree of a source storage system, the source virtual volume tree comprising source base and source snapshot virtual volumes, each representing respective versions of a plurality of extents, wherein each of the extents corresponds to a different portion of an address space of the source base virtual volume. Examples may include compressed extent collections, each comprising a compressed representation of multiple populated versions of a single extent from the source base and snapshot virtual volumes, the multiple populated versions compressed relative to one another.

Abstract: A sub-LUN ownership mapping for multiple storage controllers of a first storage array is generated. The sub-LUN ownership mapping indicates ownership of sub-LUNs by the multiple storage controllers of the first storage array. The sub-LUN ownership mapping is transmitted to a storage controller of a second storage array. A request to align sub-ownership is sent to the storage controller of the second storage array. Ownership is aligned for one or more sub-LUNS for multiple storage controllers of the second storage array.

Abstract: A sub-LUN ownership mapping for multiple storage controllers of a first storage array is generated. The sub-LUN ownership mapping indicates ownership of sub-LUNs by the multiple storage controllers of the first storage array. The sub-LUN ownership mapping is transmitted to a storage controller of a second storage array. A request to align sub-ownership is sent to the storage controller of the second storage array. Ownership is aligned for one or more sub-LUNS for multiple storage controllers of the second storage array.

Abstract: A sub-LUN ownership mapping for multiple storage controllers of a first storage array is generated. The sub-LUN ownership mapping indicates ownership of sub-LUNs by the multiple storage controllers of the first storage array. The sub-LUN ownership mapping is transmitted to a storage controller of a second storage array. A request to align sub-ownership is sent to the storage controller of the second storage array. Ownership is aligned for one or more sub-LUNS for multiple storage controllers of the second storage array.

Abstract: An example data storage system includes a first storage array having a first LUN and a second storage array having a second LUN. The first and second storage arrays may implement replication from the first LUN as a primary LUN to the second LUN as a secondary LUN. The first and second LUNs may both be an active target for host write I/O. The second storage array may, in response to receiving from a host a write that is directed to the second LUN, send write data of the write to the first storage for replication array while maintaining a copy of the write data in a fenced portion of a cache of the second storage array. The second storage array may wait to release the copy of the write data to the second LUN until a write acknowledgment is received from the first storage array.

Abstract: In some examples, with respect to distributed extent based replication, a plurality of logical unit number (LUN) extents may be ascertained for a local storage array including a LUN. A LUN owner may be assigned to the LUN. Respective access patterns used to access each of the plurality of LUN extents may be analyzed. Based on the analyzed access patterns, respective replication owners may be determined for each of the plurality of LUN extents independent of the LUN owner assigned to the LUN.

Abstract: An example data storage system includes a first storage array having a first LUN and a second storage array having a second LUN. The first and second storage arrays may implement replication from the first LUN as a primary LUN to the second LUN as a secondary LUN. The first and second LUNs may both be an active target for host write I/O. The second storage array may, in response to receiving from a host a write that is directed to the second LUN, send write data of the write to the first storage for replication array while maintaining a copy of the write data in a fenced portion of a cache of the second storage array. The second storage array may wait to release the copy of the write data to the second LUN until a write acknowledgment is received from the first storage array.

Abstract: A method generates input/output (IO) commands by plural different applications that execute on a host. The method prioritizes the applications by inserting different classifiers into the IO commands at a host bus adapter (HBA) located in the host. A storage device receives the IO commands and processes the IO commands according to priorities based on the classifiers for the applications.

Abstract: Utilization of the processor modules is monitored. A varying load pattern including at least one of a bursty behavior or an oscillatory behavior of the processor modules is identified. Distribution of logical devices between processor modules is performed.