Abstract: Techniques are provided for overlapping write handling. Overlapping write managers are used to maintain the order that write operations are executed at a first computing environment and replicated to a second computing environment. Overlapping write managers are pre-allocated as available for managing overlapping write operations. A mapping is used to track what overlapping write managers are currently allocated for particular file handles of files. Thus, if an incoming write operation targets a file handle of an already allocated overlapping write manager, then that overlapping write manager is used to execute and replicate the incoming write operation so that the order of execution of overlapping writes by the second computing environment is the same as at the first computing environment. If there is no allocated overlapping write manager for the file handle, then a new overlapping write manager is allocated and utilized.

Abstract: A system and method for enabling data replication is described. A set of protocol messages can be associated with a set of corresponding set of requests. The associated set of protocol messages can be provided to each of a source storage system and a destination storage system. The source storage system and the destination storage system can be heterogeneous storage systems that implement different types of file systems or file layouts. The source storage system and the destination storage system are enabled to perform a data replication process, in which at least a set of data is to be replicated from the source storage system to the destination storage system, using at least a protocol message from the associated set of protocol messages. The protocol message can correspond to a request for a list of snapshots stored at the source storage system.

Abstract: Techniques are provided for synchronous replication for synchronous mirror copy guarantee. A file system dependent technique for synchronous mirror copy guarantee is provided by overriding default behavior of a persistent fence so that the persistent fence is activated to block operations targeting a storage object having a synchronous replication relationship based upon the synchronous replication relationship being out of sync. The default behavior of the persistent fence is overridden to allow operations to be executed upon the storage object based upon the synchronous replication relationship being in sync. A file system independent technique for synchronous mirror copy guarantee is provided by intercepting operations before the operations are received by a file system. The operations are selectively forwarded to the file system or not based upon a state of a synchronous replication relationship.

Abstract: Techniques are provided for synchronous replication for synchronous mirror copy guarantee. A file system dependent technique for synchronous mirror copy guarantee is provided by overriding default behavior of a persistent fence so that the persistent fence is activated to block operations targeting a storage object having a synchronous replication relationship based upon the synchronous replication relationship being out of sync. The default behavior of the persistent fence is overridden to allow operations to be executed upon the storage object based upon the synchronous replication relationship being in sync. A file system independent technique for synchronous mirror copy guarantee is provided by intercepting operations before the operations are received by a file system. The operations are selectively forwarded to the file system or not based upon a state of a synchronous replication relationship.

Abstract: One or more techniques and/or computing devices are provided for utilizing snapshots for data integrity validation and/or faster application recovery. For example, a first storage controller, hosting first storage, has a synchronous replication relationship with a second storage controller hosting second storage. A snapshot replication policy rule is defined to specify that a replication label is to be used for snapshot create requests, targeting the first storage, that are to be replicated to the second storage. A snapshot creation policy is created to issue snapshot create requests comprising the replication label. Thus a snapshot of the first storage and a replication snapshot of the second storage are created based upon a snapshot create request comprising the replication label. The snapshot and the replication snapshot may be compared for data integrity validation (e.g., determine whether the snapshots comprise the same data) and/or quickly recovering an application after a disaster.

Abstract: A system and method for enabling data replication is described. A set of protocol messages can be associated with a set of corresponding set of requests. The associated set of protocol messages can be provided to each of a source storage system and a destination storage system. The source storage system and the destination storage system can be heterogeneous storage systems that implement different types of file systems or file layouts. The source storage system and the destination storage system are enabled to perform a data replication process, in which at least a set of data is to be replicated from the source storage system to the destination storage system, using at least a protocol message from the associated set of protocol messages. The protocol message can correspond to a request for a list of snapshots stored at the source storage system.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Abstract: One or more techniques and/or computing devices are provided for implementing synchronous replication. For example, a synchronous replication relationship may be established between a first storage controller hosting local storage and a second storage controller hosting remote storage (e.g., replication may be specified at a file, logical unit number (LUN), or any other level of granularity). Data operations and offloaded operations may be implemented in parallel upon the local storage and the remote storage. Error handling operations may be implemented upon the local storage and implement in parallel as a best effort on the remote storage, and a reconciliation may be performed to identify any data divergence from the best effort parallel implementation. Storage area network (SAN) operations may be implemented upon the local storage, and upon local completion may be remotely implemented upon the remote storage.

Abstract: One or more techniques and/or computing devices are provided for synchronous replication. For example, synchronous replication relationships are established between a first storage object (e.g., a file, a logical unit number (LUN), a consistency group, etc.), hosted by a first storage controller, and a plurality of replication storage objects hosted by other storage controllers. In this way, a write operation to the first storage object is implemented in parallel upon the first storage object and the replication storage objects in a synchronous manner, such as using a zero-copy operation to reduce overhead otherwise introduced by performing copy operations. Reconciliation is performed in response to a failure so that the first storage object and the replication storage objects comprise consistent data. Failed write operations and replication write operations are retried, while enforcing a single write semantic.

Abstract: One or more techniques and/or computing devices are provided for managing an arbitrary set of storage items using a granset. For example, a storage controller may host a plurality of storage items and/or logical unit numbers (LUNs). A subset of the storage items are grouped into a consistency group. A granset is created for tracking, managing, and/or providing access to the storage items within the consistency group. For example, the granset comprises application programming interfaces (APIs) and/or properties used to provide certain levels of access to the storage items (e.g., read access, write access, no access), redirect operations to access either data of an active file system or to a snapshot, fence certain operations (e.g., rename and delete operations), and/or other properties that apply to each storage item within the consistency group. Thus, the granset provides a persistent on-disk layout used to manage an arbitrary set of storage items.

Abstract: Techniques are provided for resynchronizing a synchronous replication relationship. Asynchronous incremental transfers are performed to replicate data of a storage object to a replicated storage object. Incoming write requests, targeting the storage object, are logged into a dirty region log during a last asynchronous incremental transfer. Metadata operations, executed on the storage object, are logged into a metadata log during the last asynchronous incremental transfer. Sequence numbers are assigned to the metadata operations based upon an order of execution. The metadata operations are replicated to the replicated storage object for execution according to the sequence numbers, and the dirty regions are replicated to the replicated storage object in response to the metadata operations having been replicated to the replicated storage object.

Abstract: Techniques are provided for resynchronizing a synchronous replication relationship. Asynchronous incremental transfers are performed to replicate data of a storage object to a replicated storage object. Incoming write requests, targeting the storage object, are logged into a dirty region log during a last asynchronous incremental transfer. Metadata operations, executed on the storage object, are logged into a metadata log during the last asynchronous incremental transfer. Sequence numbers are assigned to the metadata operations based upon an order of execution. The metadata operations are replicated to the replicated storage object for execution according to the sequence numbers, and the dirty regions are replicated to the replicated storage object in response to the metadata operations having been replicated to the replicated storage object.

Abstract: Techniques are provided for synchronous replication based cutover. An asynchronous replication process is executed to perform asynchronous incremental transfers of data of a storage object from a first computing environment to a replicated storage object at a second computing environment until a cutover criteria is met. A synchronous replication process is executed to synchronously replicate operations, targeting the storage object, to the replicated storage object based upon the cutover criteria being met. A cutover is performed to direct operations from targeting the storage object to targeting the replicated storage object based upon the synchronous replication process reaching a steady state of synchronous replication for sub-objects of the storage object, where operations are committed to both the storage object and the replicated storage object.

Abstract: Techniques are provided for synchronous replication based cutover. An asynchronous replication process is executed to perform asynchronous incremental transfers of data of a storage object from a first computing environment to a replicated storage object at a second computing environment until a cutover criteria is met. A synchronous replication process is executed to synchronously replicate operations, targeting the storage object, to the replicated storage object based upon the cutover criteria being met. A cutover is performed to direct operations from targeting the storage object to targeting the replicated storage object based upon the synchronous replication process reaching a steady state of synchronous replication for sub-objects of the storage object, where operations are committed to both the storage object and the replicated storage object.

Abstract: One or more techniques and/or computing devices are provided for utilizing snapshots for data integrity validation and/or faster application recovery. For example, a first storage controller, hosting first storage, has a synchronous replication relationship with a second storage controller hosting second storage. A snapshot replication policy rule is defined to specify that a replication label is to be used for snapshot create requests, targeting the first storage, that are to be replicated to the second storage. A snapshot creation policy is created to issue snapshot create requests comprising the replication label. Thus a snapshot of the first storage and a replication snapshot of the second storage are created based upon a snapshot create request comprising the replication label. The snapshot and the replication snapshot may be compared for data integrity validation (e.g., determine whether the snapshots comprise the same data) and/or quickly recovering an application after a disaster.

Abstract: One or more techniques and/or computing devices are provided for implementing synchronous replication. For example, a synchronous replication relationship may be established between a first storage controller hosting local storage and a second storage controller hosting remote storage (e.g., replication may be specified at a file, logical unit number (LUN), or any other level of granularity). Data operations and offloaded operations may be implemented in parallel upon the local storage and the remote storage. Error handling operations may be implemented upon the local storage and implement in parallel as a best effort on the remote storage, and a reconciliation may be performed to identify any data divergence from the best effort parallel implementation. Storage area network (SAN) operations may be implemented upon the local storage, and upon local completion may be remotely implemented upon the remote storage.

Abstract: One or more techniques and/or computing devices are provided for resynchronization. For example, a request may be received to create pseudo snapshots of a first consistency group, hosted by a first storage controller, and a second consistency group, hosted by a second storage controller, having a synchronous replication relationship with the first consistency group. Incoming client write requests are logged within an intercept tracking log at the first storage controller. After a first drain without hold of incoming write requests is performed, a first pseudo common snapshot of the second consistency group is created. After a second drain without hold of incoming write operations is performed, a second pseudo common snapshot of the first consistency group and the intercept tracking log is created. The pseudo snapshots and the intercept tracking log (e.g., indicating a delta between the pseudo snapshots) are used to resynchronize the first and second consistency groups.

Abstract: One or more techniques and/or computing devices are provided for synchronous replication. For example, synchronous replication relationships are established between a first storage object (e.g., a file, a logical unit number (LUN), a consistency group, etc.), hosted by a first storage controller, and a plurality of replication storage objects hosted by other storage controllers. In this way, a write operation to the first storage object is implemented in parallel upon the first storage object and the replication storage objects in a synchronous manner, such as using a zero-copy operation to reduce overhead otherwise introduced by performing copy operations. Reconciliation is performed in response to a failure so that the first storage object and the replication storage objects comprise consistent data. Failed write operations and replication write operations are retried, while enforcing a single write semantic.

Abstract: One or more techniques and/or computing devices are provided for managing an arbitrary set of storage items using a granset. For example, a storage controller may host a plurality of storage items and/or logical unit numbers (LUNs). A subset of the storage items are grouped into a consistency group. A granset is created for tracking, managing, and/or providing access to the storage items within the consistency group. For example, the granset comprises application programming interfaces (APIs) and/or properties used to provide certain levels of access to the storage items (e.g., read access, write access, no access), redirect operations to access either data of an active file system or to a snapshot, fence certain operations (e.g., rename and delete operations), and/or other properties that apply to each storage item within the consistency group. Thus, the granset provides a persistent on-disk layout used to manage an arbitrary set of storage items.

Abstract: One or more techniques and/or computing devices are provided for replicating virtual machine disk clones. For example, a first storage controller, hosting first storage, may have a synchronous replication relationship with a second storage controller hosting second storage. A virtual machine, within the first storage, may be specified as having synchronous replication protection. Accordingly, virtual machine disk clones of a virtual machine disk of the virtual machine may be replicated from the first storage to the second storage. For example, virtual machine disk clones may be synchronous replicated, replicated by a resync process invoked by a hypervisor agent, and/or stored and replicated from a clone backup directory.