I have many services running on my server and about half of them use postgres. As long as I installed them manually I would always create a new database and reuse the same postgres instance for each service, which seems to me quite logical. The least amount of overhead, fast boot, etc.
But since I started to use docker, most of the docker-compose files come with their own instance of postgres. Until now I just let them do it and were running a couple of instances of postgres. But it’s kind of getting rediciolous how many postgres instances I run on one server.
Do you guys run several dockerized instances of postgres or do you rewrite the docker compose files to give access to your one central postgres instance? And are there usually any problems with that like version incompatibilities, etc.?
I have a single big Postgres instance, shared among immich, paperless, lldap, grafana, and others. I only use the provided docker-compose as inspiration and do my own thing. It’s nicer to back up a single database (plus additional volumes, but still).
This is the correct way to look at it. Most applications that provide a docker compose do so as a convenience to get started quickly. It’s not necessarily what you should run.
It is recommended to run postgres for each service though since they may have completely different needs / configurations for the queries to be optimal. For self hosting Lemmy and matrix would be the big concerns here.
Absolute sentences like this are rarely true. Sometimes it does make sense and sometimes it doesn’t. One database is often quite capable of supporting the needs of many applications. And sometimes you need to fine-tune things for a specific application.