Systems and methods include a set of delta copies received from cluster node replicas of a replica set and stored on a main data storage on the cloud. A cloud storage service internally replicates the data from the delta copies and provides fault-tolerance and high availability against storage failures. All cluster node replicas participate in a delta copies merge. Each replica writes their deltas to an independent location in a shared storage on the cloud. Then, the delta merge includes deltas from all replicas when building a new main storage. This ensures that the data from all replicas are included in the delta merge.