RDS records the average disk throughput for RDS instances. Blue Matador monitors ReadThroughput and WriteThroughput for anomalies so you can correlate this event with any issues on the instance. Anomalous disk IO can occur for any of the following reasons:
If disk IO is consistently high and increasing, you may need to upgrade to a higher storage class. If most of your operations are reads, adding and using read replicas in an Aurora cluster may be appropriate as well.