A method for data mirroring including receiving a sequence of transactions at a first storage node from a host indicating data to be stored by the node, storing the data therein, and delineating a first batch of the transactions. The node returns to the host an acknowledgment of having stored the data, delineates a second batch of the transactions received subsequent to the acknowledgment, and conveys the data to a second storage node. The first node also conveys to the second node a first record of the transactions in the first batch and a second record of the transactions in the second batch, and the data are stored in the second node responsively to the first and second records, so that all data indicated by the transactions in the first batch are stored by the second node prior to storing data indicated by the transactions in the second batch.