I'd tried to run a really big fluid simulation with FLIP Fluids (built from source on Linux). I am not using the default fluid simulator. However, I wasn't happy with the quality of it, so I upped the resolution to some very big number. I promptly ran out of memory. Oops.
Anyways, once I set the settings, I'm wondering if there is a way for Blender to estimate (or if it isn't included, a way for me to calculate) how much RAM a fluid simulation will take. Repeatedly trying different values will take too long.