Motivation for this change

https://github.com/prometheus/prometheus/releases/tag/v2.20.0
https://github.com/prometheus/prometheus/releases/tag/v2.20.1

This release changes WAL compression from opt-in to default. WAL compression will prevent a downgrade to v2.10 or earlier without deleting the WAL. Disable WAL compression explicitly by setting the command line flag --no-storage.tsdb.wal-compression if you require downgrading to v2.10 or earlier.

Things done

Increased memory of the minio node to avoid OOM panics which happened during local execution.
Also fixed the usage of the thanos command in the test.
The test is now exposed in the package via passthru.tests.

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.