If I had to guess, the latter is because of lemm.ee, whose admin is from there (according to GitHub).

i had mine up for about a week, been running lcs for quite a few days, and both actively use other spaces (like this one) and post a lot in the ones on my instance. currently i’m sitting at 4.5 GB for pictrs (not a typo, that’s what the picture server is called), 2.3 GB for the postgres database, and 5.4 GB for docker. total disk usage is about 14 GB for now, i expect it to grow in the future but idk yet how fast it will be. people are reporting about 100 MB a day since the reddit migration, and tbh that might check out.

if you’re hosting it on your own nas you’re probably gonna be fine space-wise. i’d just recommend to layer a vpn and/or a cache in-between – i don’t know exactly how to do this, i went straight for the cloud route, but i have seen people in !selfhosted@lemmy.world doing that, and the lemmy admin matrix chat is nice too.

just fyi, your instance does have to be reachable on a domain if you want federation to work. also, keep everything you can on the defaults and only change things one by one, the error messages are not very helpful. i spent like a day trying to debug why lemmy wasn’t starting up at first, turns out i just had an instance name longer than 20 characters.

I’ve had my own instance running on a puny 1VCPU/1G RAM instance at Vultr since the beginning of June and the resource usage has been negligible. Drive space is the largest resource it’s consumed, it’s at about 12GB of drive space consumed in a month.