Kapacitor Capacity Planning

We have a 8 core 32GB RAM kapacitor node, want to understand how much stream data a 32GB RAM system can take at a time. Is there a math behind this calculation?

What is the best way to capacity plan for Kapacitor nodes?

What is the best indicator for upgrading more memory in a Kapacitor node?

How does Kapacitor handle stream data if memory used exceeded total memory? Are data getting dropped? Will Kapacitor logs output any errors?