I plan to start working on my small setup for personal use. While I'm already pretty on certain on what I'll use on the software side (2 different server with CEPH in network, with an erasure coding (k=2 and k+m=4))

I plan to start with 4 4TiB HDD (plus maybe a small SSD for cache). I already have two laptops with broken screen laying around, and would like, to minimize initial investement, reuse them, and just them into the USB's connection (and connect them with a switch via Ethernet, plus maybe an overlay network if it work well)

I would like to know if someone have recommandation for getting these hard drive? For tax avoidance reason, it is important for them to be internal HDD (as they are considerably less taxed than USB HDD for stupid reason)