1. A method for storing data in one or more data storage systems by selecting from among at least a first operating mode and a delta replication operating mode, comprising: storing data pursuant to the first operating mode; ascertaining a first status of a criterion pertaining to an activity performed by the one or more data storage systems while operating in the first operating mode; monitoring a change in the criterion to a second status; in response to the change, storing data pursuant to the delta replication operating mode.