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.

Methods and systems for managing manifests for replication are provided. A system includes a number of origination nodes forming a source array. A remote copy ticket dispenser provides a replication ticket for a transaction to be grouped with other transactions and to be replicated to a destination array. A transaction communicator sends transactions to the destination array.

One or more techniques and/or systems are provided for dynamic mirroring. A first storage node and the second storage node within a first storage cluster may locally mirror data between one another based upon a local failover partnership. The first storage node and a third storage node within a second storage cluster may remotely mirror data between one another based upon a primary disaster recovery partnership. If the third storage node fails, then the first storage node may remotely mirror data to a fourth storage node within the second storage cluster based upon an auxiliary disaster recovery partnership. In this way, data loss protection for the first storage node may be improved, such that the fourth storage node provide clients with access to mirrored data from the first storage node in the event the second storage node and/or the third storage node are unavailable when the first storage node fails.

The present disclosure provides a method, system, and device for security object synchronization at multiple nodes of an active-active environment. To illustrate, a source node may generate a corresponding security object sync request for each of multiple target nodes. The source node may send the security object sync request to the target nodes via a source queue and, for each target node, a corresponding distribution queue. A distribution queue may be closed based on an acknowledgement received from a corresponding target node, after a time period, or after a number of transmission attempts. A synchronization log may be maintained to indicate which security object sync requests have been delivered to which target nodes. In some implementations, the source node and the target nodes are part of an active-active environment that may be synchronized in time so the nodes resolve conflicts between received security object updates initiated from two different nodes.

Maintaining a synchronous replication relationship between two or more storage systems, including: receiving, by at least one of a plurality of storage systems across which a dataset will be synchronously replicated, timing information for at least one of the plurality of storage systems; and establishing, based on the timing information, a synchronous replication lease describing a period of time during which the synchronous replication relationship is valid, wherein a request to modify the dataset may only be acknowledged after a copy of the dataset has been modified on each of the storage systems.

Replicated instances in a database environment provide for automatic failover and recovery. A monitoring component can periodically communicate with a primary and a secondary replica for an instance, with each capable of residing in a separate data zone or geographic location to provide a level of reliability and availability. A database running on the primary instance can have information synchronously replicated to the secondary replica at a block level, such that the primary and secondary replicas are in sync. In the event that the monitoring component is not able to communicate with one of the replicas, the monitoring component can attempt to determine whether those replicas can communicate with each other, as well as whether the replicas have the same data generation version. Depending on the state information, the monitoring component can automatically perform a recovery operation, such as to failover to the secondary replica or perform secondary replica recovery.

Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

Data are maintained in a distributed computing system that describe a graph. The graph represents relationships among items. The graph has a plurality of vertices that represent the items and a plurality of edges connecting the plurality of vertices. At least one vertex of the plurality of vertices includes a set of label values indicating the at least one vertex's strength of association with a label from a set of labels. The set of labels describe possible characteristics of an item represented by the at least one vertex. At least one edge of the plurality of edges includes a set of label weights for influencing label values that traverse the at least one edge. A label propagation algorithm is executed for a plurality of the vertices in the graph in parallel for a series of synchronized iterations to propagate labels through the graph.

Managing storage systems that are synchronously replicating a dataset, including: detecting a change in membership to the set of storage systems synchronously replicating the dataset; and applying one or more membership protocols to determine a new set of storage systems to synchronously replicate the dataset, wherein the one or more membership protocols include a quorum protocol, an external management protocol, or a racing protocol, and wherein one or more I/O operations directed to the dataset are applied to a new set of storage systems.

A plurality of failure domains are communicatively coupled to each other via a network, and each of the plurality of failure domains is coupled to one or more storage devices. A failure resilient stripe is distributed across the plurality of storage devices, such that two or more blocks of the failure resilient stripe are located in each failure domain.