Hi all, i'm new to this list :) My setup: MySQL Server 5.5.37 -> Replication -> Galera 10 Cluster (currently 2 nodes) The old MySQL Master is receiving inserts to a table with a auto_increment field (primary key). The Galera Cluster is configured as classic slave to the master. From time to time i'm getting duplicate entry issues on the galera cluster: 140905 12:06:15 [ERROR] Slave SQL: Error 'Duplicate entry '16383' for key 'PRIMARY'' on query. ... 140905 12:06:15 [Warning] Slave: Duplicate entry '16383' for key 'PRIMARY' Error_code: 1062 I cannot see the problem where there could came from... My thought was if the insert (auto_increment) succeeds on the master then is must also succeed on the galera side... someone with an idea on it? BR Otto