New Raspberry Pi Server
When I upgrade my desktop PC I tradtionally retire my old server and use the replaced PC in its place. Also taking the opportunity for a clean install of Ubuntu server. I recently realised that the machine currently serving that role is overkill for what I need, namely:
A large desktop machine with 6GB RAM and a big PSU is unnecessary.
I switched to a Raspberry Pi 4 with 4GB RAM, got a little cooling fan for it and set up a simple Ubuntu server. The Pi4 has gigabit ethernet and USB3 support. For files I purchased a 4GB WD Passport drive that can be powered from the Pi's USB3 port. I only have about 2GB of data right now, so room to grow.
Backing this up to two 2GB external drives became tiresome and wasn't happening as often as it should. I purchased a second 4GB Passport drive planning to rsync nightly rather than use software RAID. Unfortuntely there just wasn't enough power from the Pi4 to support two drives.
I realised this was a blessing in disguise. Installing Ubuntu server on a Raspberry Pi and plugging the second 4GB drive in to that would give me the nightly rsync backup I need. The 100mb speed of the Pi3's NIC and USB2 would be slow in comparison, but more than enough for a nightly backup run. Not to mention the peace of mind in knowing if the Pi4 went up in smoke it could take all my data and I'd still have a working backup.
This also meant I could spread the resource load. I moved the PiHole over the Pi3 as it's only DNS traffic. I'm also using it to serve a few old, separately-powered external drives over the network. I can use the Pi3 to try things out and easily rebuild in case I screw up without taking my main fileserver offline.
I had a spare five-port gigabit network switch that I dedicated to use with this little server array, keeping it all in a plastic box.
While technically this met my needs of emulating my old server's abilities, as well as cutting power consumption, it was inelegant. Three power-bricks, and two long USB cables to bridge a gap mere inches in length.
I checked the power-consumption of the switch, which turned out to be 5v 0.7a. The Pi4 needs a good 3a, and the Pi3 2.5a, both 5v. That's about 6.2 amps for the whole thing.
I hopped on one of those Chinese online stores and ordered a 12v 8a power brick, a short micro-usb cable to power the pi3, and a short USB-C cable to power the pi4.
To split the 12v and get it to three 5v devices I wired a connector block in parallel to three 12v-5v buck converters.
With two 30cm cat5e cables I now have a single 12v power brick and a single network cable running the whole thing. I also have two spare network ports, and about 1.8 amps of power going begging.
Maybe I'll put a Raspberry Pi Zero (or similar SBC), or maybe an ESP32 in there and set up some LoRa.
In hindsight, I could've used a 5v power supply (with enough current), but I hadn't finalised the setup and wasn't sure everything I might want to power would be 5v. As it stands, I'm thinking of hooking up an old 12v case fan to move some air around everything.