thanks for trying to help out. just checked, this is how I'm running it:

    while : ; do SYNAPSE_CACHE_FACTOR=0.01 python -B -m synapse.app.homeserver -c homeserver.yaml  ; sleep 20 ; done

I'm not even using runit or anything; I set it up like this several months ago and haven't bothered touching it since because it's been relatively solid and reliable.

Even at a "cache factor" of 0.01, my tiny DO droplet is still swapping and eventually the homeserver gets OOM killed.