well your ram in your computer aren’t critical either… i’m sure your system will do fine if you injected corrupt data into them…
the fact is you cannot really predict what would happen in most cases… so yes the databases are not critical for the storagenode integrity but damage to them could have nearly unpredictable outcomes…
i cannot say how bad it could be (kinda requires me to know how the storagenode works in detail), but i would seriously try to avoid doing to risky stuff with them.
like putting them on a ram drive, besides whats the gain from that… you most likely won’t get it to run much faster than with a proper ssd.
you would however end up using a few GiB to having the databases in RAM, you would be forced to have ECC memory, do regular scrubs of your RAM to ensure the data integrity of the entire db at all times… just to get performance thats most likely equal or to practical performance basically irrelevant.
with ZFS i barely even know where my database is located… some of it would be in ram, and then it would most likely also be in my L2ARC ssd and then it would be written to disk from my slog ssd when it flushes… so i basically have the database in ram, but i don’t have any of the downsides of using a RAM drive… only most of the advantages… and i could go hot pull most of my RAM and my L2ARC and my system would just run a bit slower… because of how my server is setup it doesn’t rely on those things as being critical components for operation and all of them are hotswap.
tho granted the OS might crash… not sure how well debian is programmed to deal with somebody pulling RAM on it while live.
but then the watchdog of the BMS would register the system as frozen and reboot after 10 minutes, and everything would just boot up and continue and be may have forgotten a few ms of what it was doing because the slog didn’t catch it in time and none of the data would be corrupt because it’s Copy On Write, thus it cannot create write holes during lockup or power outages.
i duno what you are running, but doing a RAM drive for the DB would most likely be a semi dangerous waste of resources…when there are so many much more practical solutions that can benefit your system in may more ways.
but if you do put you DB in RAM do let us know how it turns out and if you do see any actual performance gains… always interested in learning new optional tricks, or hear a horror story about how not to setup ones system…