GT.M database replication ensures that the originating instance and its replicating instances are logically identical, excluding latency in replication. During rolling upgrades, the originating instance and its replicating instances are logically equivalent but the exact storage of M global variables may differ. FIS recommends you to ensure that all database updates to replicated regions must occur only on the originating instance. GT.M replicates all changes on the originating instance to its replicating instances.