Extent migration is provided in a data storage environment configured for synchronous replication between a primary and secondary pair of storage entities, each having tiered storage devices. In one embodiment, by way of example only, a migration instruction is sent, by the primary storage entity, to the secondary storage entity, the migration instruction including a time delta approximately equal to a time of an intended migration at the primary storage entity adjusted for a transmission time such that the primary and secondary storage entities conduct the extent migration at approximately a same time.