meronense OOM

today, metrics.tpo went down because the OOM killer was invoked. not sure what happened. i restarted both metrics-r and metrics-web.service, pending further investigation.

this happened before, of course. we bumped the memory on that box to 20GB in #41335 (closed) and had issues after the bullseye upgrade as well (#40814 (closed)), both incidents should be investigated. those are just the incidents that pop up in the gitlab "Similar issues", further investigation in other issues probably warranted.

possibly related with the bookworm upgrade, of course (#41252 (closed)).