A method for synchronous replication of stream data includes receiving a stream of data blocks for storage at a first storage location associated with a first geographical region and at a second storage location associated with a second geographical region. The method also includes synchronously writing the stream of data blocks to the first storage location and to the second storage location. While synchronously writing the stream of data blocks, the method includes determining an unrecoverable failure at the second storage location. The method also includes determining a failure point in the writing of the stream of data blocks that demarcates data blocks that were successfully written and not successfully written to the second storage location. The method also includes synchronously writing, starting at the failure point, the stream of data blocks to the first storage location and to a third storage location associated with a third geographical region.

A system and method include reception, at a primary storage unit, of a first write request from a client including a first key and a first value, persisting of the first value in a first non-volatile memory of the primary storage unit in association with the first key, broadcast of the first write request and a first set of globally-durable keys to the one or more secondary storage units, reception, from each of the one or more secondary storage units, of an acknowledgement of the first write request and a first set of locally-durable keys, each of the first sets of locally-durable keys including the first key, reception, at the primary storage unit, of a second write request from the client including a second key and a second value, persisting of the second value in the first non-volatile memory in association with the second key, and broadcast of the second write request and a second set of globally-durable keys to the one or more secondary storage units, the second set of locally-durable keys including the first key.

Aspects of the present disclosure involve systems and methods for removes and/or adding log and/or cache devices to storage pools of a storage appliance. Users, via a graphical-user interface, identify the log and/or cache devices for removal or addition. Subsequently, the log and/or cache devices are moved, according to a data profile corresponding to the devices, from a first storage appliance to a second storage appliance.

A clustered pair of storage systems configured for active-active bidirectional synchronous replication expose a stretched volume over paths to both storage systems. Writes to the stretched volume received at each system are replicated to the peer system. The cluster can use a time-to-live (TTL) mechanism by which a non-preferred system continuously requests a TTL grant from the preferred system to remain in the cluster. Algorithms that reduce or avoid data unavailability are described and can include assessing the health of the systems in the cluster. An unhealthy system can trigger a one-sided polarization algorithm to notify the peer system that it is polarization winner. An improved polarization technique using a witness to decide the polarization winner includes a system adding a time delay before contacting the witness if the system is unhealthy. A control component can detect an unhealthy system and disable the active-active bidirectional synchronous replication.

A method for execution by a computing device of a dispersed storage network (DSN). The method begins with obtaining a plurality of write requests. The method continues where for a write request of the plurality of write requests, the computing device generates a vault identification and a generation number. The method continues where the computing device obtains a rounded timestamp and a capacity factor and generates a temporary object number based on the rounded timestamp and the capacity factor. The method continues where the computing device generates a temporary source name based on the vault identification, the generation number, and the temporary object number. The method continues where the computing device identifies a set of storage units of a plurality of sets of storage units of the DSN based on the temporary source name.

A technique provides efficient data failover by creation and deployment of a protection policy that ensures maintenance of frequent common snapshots between sites of a multi-site data replication environment. A global constraint optimizer executes on a node of a cluster to create the protection policy for deployment among other nodes of clusters at the sites. Constraints such as protection rules (PRs) specifying, e.g., an amount of tolerable data loss are applied to a category of data designated for failover from a primary site over a network to a plurality of (secondary and tertiary) sites typically located at geographically separated distances. The optimizer processes the PRs to compute parameters such as frequency of snapshot generation and replication among the sites, as well as retention of the latest common snapshot maintained at each site to create a recovery point and configuration of the protection policy that reduces network traffic for efficient use of the network among the sites.

A storage system has a cluster structure in which a node is connected with a different node, the node having a volatile memory for storing first update data from a host and a first non-volatile memory for storing second copy data of second update data from the host to the different node, and having a copy management processing unit for storing first copy data of the first update data into a second non-volatile memory of the different node, and a storage service processing unit for transmitting, to the host, a response with respect to an update request of the first update data in response to the storage of the first copy data of the first update data by the copy management processing unit into the second non-volatile memory of the different node.

A method, device, and non-transitory computer readable medium for minoring data, comprising, selecting, based on a plurality of data attributes, a portion of local data in a local storage device for minoring to a remote storage device and copying the selected portion of the local data to at least one cache memory of the remote storage device. Next a determination of when a failover event has occurred in the local storage device is made, wherein the failover event comprises an event in which the local data in the local storage device is inaccessible to a client computing device when the client computing device attempts to access the local data from the local storage device. A copy of the local data from the cache memory in the remote storage device is retrieved when the failover event is determined to have occurred.

Configuration and replication can be managed across multiple sites for datacenter volumes. A visual representation of a current configuration for a first of a plurality of replication techniques can be conveyed for display on a display device. Changes can be made to the current configuration, producing a future configuration. The future configuration can be analyzed for replication errors, and an updated visual representation can be produced that identified discovered replication errors and highlights differences between the current configuration and the future configuration. The updated visual representation can be conveyed, for display on a display device.

A method for increasing the efficiency of copying data is disclosed. In one embodiment, such a method includes receiving a request to copy data from a first location to a second location. The method determines an original copy algorithm associated with the request and determines whether the original copy algorithm is the best copy algorithm available to copy the data. If the original copy algorithm is the best copy algorithm, the method uses the original copy algorithm to copy the data. If, however, the original copy algorithm is not the best copy algorithm available, the method substitutes a more efficient copy algorithm for the original copy algorithm. In certain embodiments, this may be accomplished by looking in a prioritized list of copy algorithms and selecting a more efficient copy algorithm from the list. A corresponding system and computer program product are also disclosed.