Comment by ssl-3

Yep. They be wrong. Many of the myths about ZFS seem to originate from the TrueNAS forums, and the working assumption is that they're motivated to be this way because they're a bunch of gatekeeping losers.

More RAM is better -- of course it is. Otherwise-unused RAM can gets used for stuff like caching (such as the ZFS arc), and caches are faster than disks. That's good for performance.

But ZFS isn't really any more thirsty in this way than other filesystems are, unless special features -- stuff that many other filesystems lack entirely, like deduplication -- get used.

And these days, dedup can use an SSD instead of RAM for the heavy lifting so that's not a huge concern either. (Not that I'm recommending dedup; it works and it is reliable, but it doesn't fit very many workloads.)

I would absolutely be comfortable running ZFS with 12TB on 6GB. Or 2GB, for that matter. It's fine. Send it.

I've personally done more with less and had excellent results. No regrets.

(There's ways to tune arc performance, too. As an example, I've got a dataset that is full of many terabytes of Linux ISOs. I don't need that data to be cached...like, ever. If it were to be cached, it would just consume resources that would be better spent elsewhere. But I do want it to be indexed quickly. So I set that dataset to primarycache=metadata and that works great for me.)