Coordinating write sequences in a data storage system

According to one aspect of the present disclosure, a method and technique for coordinating write sequences in a data storage system is disclosed. The method includes: responsive to a primary device receiving a request to write to primary storage, receiving from the primary device a request for a sequence number; generating a current sequence number for the write; generating a first identifier indicating an identity of secondary devices writing to secondary storage based on the current sequence number; generating a second identifier indicating an identity of secondary devices writing to secondary storage based on the current sequence number and a previous sequence number; transmitting the current sequence number and the second identifier to the primary device; and transmitting the current sequence number and the first identifier to the secondary devices writing to secondary storage based on the previous sequence number.