Replication Summary
MySQL replication copies data from primary to replicas via the binary log. Use GTID mode for robust setup, monitor lag and thread health, separate reads to replicas, and use delayed replicas as rolling backups.
MySQL
Beginner
3 min read
MySQL Replication Summary
Example
-- Replication health quick checks:
SHOW REPLICA STATUS\G -- lag, errors, thread status
SELECT * FROM performance_schema.replication_applier_status_by_worker\G
-- Key metrics to alert on:
-- Seconds_Behind_Source > 30
-- Replica_IO_Running != Yes
-- Replica_SQL_Running != Yes
-- Last_Error != "" Pro Tip
Replication is not a backup — it replicates deletes and drops instantly. Keep separate backups.