We mostly care about the cpu/memory/storage metrics for mysql. I found another interesting metrics, it’s the aborted clients. What is it? It’s the number of the client is unable to authenticate to your servers. Why does it matter? There are a few reason why the client is unable to connect: your server is reaching the maximum connections, the user is using wrong password.

If this value is showing, it means we are not fully operational. It’s good for proactive action on this.