Redis will persist application files (eg dump.rdp) to disk from wherever it was launched. We're currently launching from the root of the repo, so I'm constantly getting a dump.rdp in my git working copy which is annoying (as would everyone else if they were actually using Redis/MariaDB via Nix...).
Instead we're cding to $REDIS_CACHE_DIR before launching Redis, so dump.rdp will live there and outside of the root of the repo.