I built a 24 TB HDD NAS in a 36 bay chassis for around $1000 all-in: mb, ram, rails, chassis, rack, disks, hba, nic
Awful Watts/TB but the plan is to run it and the GPU rig on solar.
The nice thing about the array being big is that I can just RAID 1 it instead of worrying about tinkering with RAID 5, and leave a drive as a hot spare.
PCIe 2.5G NIC for the uplink, and then it can serve over SMB or iSCSI. The main use case for this thing, incidentally, is it just is a caching proxy that holds Docker images, models off of Huggingface, and so on.
I fell in love with the silly idea of squeezing 10G NIC + 10G writes (to a 2x12 RAID 10 HDD array) on the thunderbolt bus of my 12 year old macbook pro.
Then I got distracted with the server mb and truenas and ZFS.
Can't you get that in a single disk that costs less than a kilodollar?