Yes, you understand it correctly that you can integrate existing prometheus with OpenObserve for long term storage of metrics with s3.

And yes you can get your logs there too.

You don't need grafana as OpenObserve has good dashboarding for metrics and logs built in. Still early days for OpenObserve - some features are missing and has some rough edges.

I am not sure what you mean by:

> does it mean that long term metrics mirrored from prometheus are no longer available there?

> is there any way to get just graphana plugin for self hosted deployment?

ping us on slack channel, If you are able to make friends with the team you can get anything :-) . Fair warning - We have found OpenObserve logs UI to be much smoother and advanced than grafana UI.