Sizing of microservices

Info

What is the correct sizing of 30_Knowledge/Microservices?

Opinions

Ich präferiere grobgranulare Ansätze. Nicht so komplex wie Netflix.
– Eberhard Wolff

Can you understand everything it does, does it fit in your head? If you can’t – and that is usually the case when something is doing more than one thing – you might want to think about splitting it up.
— James Lewis (HOW BIG SHOULD A MICRO-SERVICE BE?)

However, don't be fooled by the size of those microservices, because a lot of those so-called microservices at Netflix are a lot larger, just looking at the code base, than the big monoliths that I've worked at, at many other companies. Some of these systems are really big. There's a lot of code there.

My opinion

The size only should not be the reason to split a service. You should only do that if you have good reasons for it, e.g. business requirements, scaling problems, etc.

The size of a microservice should match the problem domain and how well one team can maintain it considering cognitive load.

Challenge data consistency

laigner.etal.2021.datamanagementmicroservices (pg. 10)

“microservices made people separate code when they should not be separated, causing this eventual consistency everywhere. [...] people wanted to create a separate microservice, just because of ‘size’, and we end up having consistency problems.”