AWS Aurora Serverless unexplained write IOPS

Question

I've created an RDS Aurora Serverless cluster with a maximum ACU of 1 and have noticed a high number of Volume Write IOPS, despite not creating a database or ever connecting to the cluster:

I've looked through the general_log and noticed this statement, which is executed approximately every 2 seconds:

INSERT INTO mysql.rds_heartbeat2(id, value) values (1,1607638395773) ON DUPLICATE KEY UPDATE value = 1607638395773 ;

This would explain some of the Write IOPS but nothing close to the 550 per minute that the graph is showing.

Can someone explain where these IOPS are coming from?

Answer 1

The VolumeWriteIOPs and VolumeReadIOPs are pretty misleading due to their name. Ps does not stand for "per second". The metric is the sum of IO operations in a five-minute interval. You can calculate the per-second value by dividing it by 300. That leads to around 2 IO per second in your case.