A data replication method and a storage system are provided. The method is applied to a storage system including a first storage device and a second storage device. According to the method, after determining replication information, a first storage system determines a first replication sub-information and a second replication sub-information according to the replication information, where the replication information is used to indicate data that needs to be replicated by the first storage system to a second storage system in a current replication task. Then, the first storage device replicates data to the second storage system according to the second replication sub-information, and the second storage device replicates data to the second storage system according to the second replication sub-information.

A data replication method includes obtaining differential data information corresponding to differential data, where the differential data information includes a storage address of the differential data, and a determining value of the differential data, replicating the differential data from the primary volume to the secondary volume according to the storage address of the differential data that is located in the primary volume when the determining value is not less than a preset threshold, and taking a snapshot for the primary volume when the determining value is less than the preset threshold and replicating the differential data to the secondary volume.

Systems and methods are disclosed to improve disaster recovery by implementing a scalable low-loss disaster recovery for a data store. The disaster recovery system enables disaster recovery for a linearizable (e.g., externally consistent) distributed data store. The disaster recovery system also provides for a small lag on the backup site relative to the primary site, thereby reducing the data loss by providing a smaller data loss window compared to traditional disaster recovery techniques. The disaster recovery system implements a timestamp for log records based on a globally synchronized clock. The disaster recovery system also implements a watermark service that updates a global watermark timestamp that a backup node uses to apply log records.

Transforming data that is provided by a first instance of an application that uses application-instance specific data includes determining if a component of the data is an application-instance specific component and, if the component is an application-instance specific component, transforming the component either at a storage system containing the data or as the component is being accessed by a second instance of the application, different from the first instance. Transforming the component at a storage system containing the data may be performed independently of any accesses of the data. Transforming the component at a storage system containing the data may be performed by the storage system. The first instance of the application may run on a first host and the second instance of the application may run on a second host different from the first host. The first and second instances of the application may run on a same host.

Providing Quality of Service (QoS) for replicating datasets including: receiving, by a target data repository from a source data repository, a checkpoint describing one or more updates to one or more datasets stored in the source data repository and the target data repository; adding, by the target data repository, the checkpoint to a first queue for checkpoints directed to one or more volumes in the target data repository, wherein the first queue is included in a plurality of queues for the target data repository; selecting, by the target data repository, one or more queues from the plurality of queues; and servicing an operation from each of the selected one or more queues.

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.

A secondary location is configured as a recovery service for a primary location of the service. The secondary location is maintained in a warm state that is configured to replace the primary location in a case of a failover. During normal operation, the secondary location is automatically updated to reflect a current state of the primary location that is actively servicing user load. Content changes to the primary location are automatically reflected to the secondary location. System changes applied to the primary location are automatically applied to the secondary location. For example, removing/adding machines, updating machine/role assignments, removing adding/database are automatically applied to the secondary location such that the secondary location substantially mirrors the primary location. After a failover to the secondary location, the secondary location becomes the primary location and begins to actively service the user load.

A system and method include migrating, by a migration controller, a first entity of a first subset of entities from a source site to a target site in a virtual computing system based on an asynchronous mode of replication. The system and method also include replicating, by the migration controller, data of a second entity of a second subset of entities from the source site to the target site based on a synchronous mode of replication in parallel with the migration of the first entity for dynamically adjusting a recovery time objective parameter.

A server system includes a primary server, at least one synchronous backup server, and at least one asynchronous backup server. The primary server includes a first processor. The at least one synchronous backup server, each includes a second processor configured to back up data of the primary server in a synchronous manner. The at least one asynchronous backup server, each includes a third processor configured to back up data of the primary server in an asynchronous manner. The first processor is configured to control each of one or more of the at least one asynchronous backup server to operate as a synchronous backup server when a number of the at least one synchronous backup server decreases due to a failure in at least one server included in the server system.

An aspect includes determining a host write rate based on a number of chunks written to a storage volume during a first replication cycle and determining a target rate based on an estimated number of chunks written during a second replication cycle. The target rate is determined by dividing the number of chunks written during the second replication cycle by a recovery point objective (RPO) period. An aspect also includes transmitting chunks written during the second replication cycle at the target rate.