Organization of storage on an old computer with a bunch of different old screws - which way to choose?

Question

Data archiving

There are a bunch of old hard drives with volumes from 100 to 1000 GB, a new working computer and an old one, but also quite working. I want to organize all these screws as one big "backup store". Apparently, in order not to stick them one by one and manually copy the necessary information, it is better to insert them all (or almost all) into the old computer and make something like a server out of it, which I will turn on at the right time. The question is what is the best way to do this? On Freenas or Windows Server? I read about them in different branches, but I still have a few questions.
1, the biggest one is in fault tolerance. Because since the screws are old, then there is a high probability that one of them will fail and, if I understand correctly, in the case of Freenas, this will kill everything. Or not? It is necessary that if one fails, the data from the other would be recoverable.
2. It would be nice to be able to connect a new screw to this storage (even if it will be displayed as a separate logical drive), where is this possibility?
3. Or maybe it’s easier to organize everything on the basis of the existing old system, which is quite working (which I will keep anyway just in case)?
I will be very glad to any answers and councils. I'm pretty new to things like this :)

Answer 1

"Beginner" and "data storage systems", alas, are not compatible. You'll have to quickly become an old man.
Topics are:
RAID and its levels (you are interested in 0,1,6,10)
MDADM
LVM
iSCSI
The general answer is that the above tools will allow you to assemble fault-tolerant storage from junk. However, keep in mind that an "old computer" usually contains an old power supply, and hard drives are a gluttonous thing.

Answer 2

I think old hardware is not a good option for some kind of backup!