In a statement-based replication (SBR) setting (see Replication Formats for details), whenever the SQL thread for the slave is stopped (for example, during a slave shutdown that has to occur when you restore a backup to a slave server), all temporary tables that are open then will not get replicated on the slave (see Replication and Temporary Tables for details). That means it is not always safe to backup a slave server in an SBR setting with mysqlbackup if temporary tables might be created on the master, as the temporary tables might be missing from the backup, making it inconsistent. Therefore, only use mysqlbackup with an SBR slave if you know no temporary tables are created on the master.