

That whole “1 GB per TB of capacity” is some generic rule someone made up once that doesn’t really have anything backing it up. It depends completely on your use case. If it’s mostly media storage that is rarely accessed, I’m sure that 4 GB is plenty.
I run a beefy TrueNAS server for a friends video production company with a 170 TB ZFS array, right now ARC is using 40 GB of RAM with 34 GB free that it’s not even bothering to touch, I’m sure most of the ARC space is just wasted as well. That’s just one example of how 1 TB = 1 GB makes no sense.

No deduplication. Before replying I tried doing some research to find where the 1 TB/1 GB rule came from originally but couldn’t find any original source, and everything I found said that was without deduplication, for dedup its supposed to be more like 5 GB/TB (no idea how true that is either)
Yeah, TB, oops, edited thanks!