Abstract: Embodiments of the present invention relate to asynchronously replicating data in a distributed computing environment. To achieve asynchronous replication, data received at a primary data store may be annotated with information, such as an identifier of the data. The annotated data may then be communicated to a secondary data store, which may then write the data and annotated information to one or more logs for eventual replay and committal at the secondary data store. The primary data store may communicate an acknowledgment of success in committing the data at the primary data store as well as of success in writing the data to the secondary data store. Additional embodiments may include committing the data at the secondary data store in response to receiving an instruction that authorizes committal of data through a identifier.

Abstract: Embodiments of the present invention relate to invoking and managing a failover of a storage account between partitions within a distributed computing environment, where each partition represents a key range of data for the storage account. The partitions affected by the failover include source partitions hosted on a primary storage stamp and destination partitions hosted on a secondary storage stamp, where the storage account's data is being actively replicated from the primary to the secondary storage stamp. Upon receiving a manual or automatic indication to perform the failover, configuring the source partitions to independently perform flush-send operations (e.g., distributing pending messages as a group) and then configuring the destination partitions to independently perform flush-replay operations (e.g., aggressively replaying currently pending transactions).

Abstract: Presented herein are methods of continuously verifying data and repairing errors introduced during replication. In a particular embodiment, a primary data store sends out information sufficient to create a checkpoint together with a checksum for the data being verified at that checkpoint. At the secondary data store, a checkpoint is created in accordance with the checkpointing information, and a checksum is calculated over the indicated data at the created checkpoint. If the calculated checksum disagrees with the received checksum, additional checksums are calculated over subranges of the indicated data and compared with corresponding checksums over the data at the primary data store. The checksums at the primary data store may be requested from the primary data store or calculated locally based on the received overall checksum. Once an erroneous entry is identified, it can then be re-replicated from the primary data store to restore data consistency.

Abstract: Embodiments of the present invention relate to synchronously replicating data in a distributed computing environment. To achieve synchronous replication both an eventual consistency approach and a strong consistency approach are contemplated. Received data may be written to a log of a primary data store for eventual committal. The data may then be annotated with a record, such as a unique identifier, which facilitates the replay of the data at a secondary data store. Upon receiving an acknowledgment that the secondary data store has written the data to a log, the primary data store may commit the data and communicate an acknowledgment of success back to the client. In a strong consistency approach, the primary data store may wait to send an acknowledgement of success to the client until it receives an acknowledgment that the secondary has not only written, but also committed, the data.

Abstract: Embodiments of the present invention relate to invoking and managing load-balancing operation(s) applied to partitions within a distributed computing environment, where each partition represents a key range of data for a storage account. The partitions affected by the load-balancing operation(s) are source partitions hosted on a primary storage stamp and/or destination partitions hosted on a secondary storage stamp, where the primary and secondary storage stamps are located in geographically distinct areas and are equipped to replicate the storage account's data therebetween. The load-balancing operation(s) include splitting partitions into child partitions upon detecting an increased workload as a result of active replication, merging partitions to form parent partitions upon detecting a reduction in workload as a result of decreased processing-related resource consumption, or offloading partitions based on resource consumption.