Robust data replication

Abstract

Disclosed is a system for replicating data. The system may comprise a plurality of nodes preferably organized in groups with one of the nodes acting as a coordinator node. The nodes are configured to receive write requests from an external server and to apply these write requests to a data storage source of the data storage system. The write requests typically belong to a batch of independent write actions identified by a batch sequence number. Each node stores the write request in non-volatile memory with the coordinator node monitoring which batches are secured in their entirety in non-volatile memory. The coordinator node authorizes all other nodes to sequentially replicate the write requests in their non-volatile memory to the data storage source for all writes up to the highest batch sequence number for which all writes have been secured in non-volatile memory.