CloudWatch metrics for DB instances
Amazon CloudWatch also contains metrics that Amazon RDS publishes automatically. The metrics that reside
      in the AWS/RDS namespace are instance-level metrics, which
      refers to the Amazon RDS (service) instance (that is, the isolated database environment running in
      the cloud) rather than the DB instance in the strict sense of the mysqldCPUUtilization, WriteIOPS,
        SwapUsage, and others. Nevertheless, there are some DB instance metrics that
      are applicable to MariaDB and MySQL:
- 
        BinLogDiskUsage– The amount of disk space occupied by binary logs.
- 
        DatabaseConnections– The number of client network connections to the DB instance.
- 
        ReplicaLag– The amount of time a read replica DB instance lags behind the source DB instance.