At this moment, I have an HP Microserver Gen8 as a NAS. Next to it, I have my old homeserver that I bought 10 years ago, to host Home Assistant and some Docker containers.

This is a historical grown situations. I started with the Microserver just as a NAS. When thinking about running some applications on a server, a few options came along. Either I could upgrade my NAS (it fits a Xeon, and the memory could be increased), or buy something new. The easiest solution at that time however was to start using my old machine that I still had laying around. With a 3th gen Core i5 and 32 GB memory it had more than enough power, and it was free, as I already had it. This had the additional benefit of separating storage and compute. So, that I could make stability and security of my NAS a priority.

But, with electricity prices increasing, I was more and more frustrated by the fact that the combination uses 80 watt. That is 700 KWh per year.

It should be possible to reduce this significantly, by combining these servers, and replacing them by something more power efficient. And thus my search began. My current setup:

NAS:

  • 80 GB X25M boot SSD
  • 2x4 TB in RAID 1 for my main storage
  • 1x3 TB for backups
  • 1x3 TB as cold-standby (ok, I was just too lazy to install that drive..)
  • Only thing I use on my NAS is Samba
  • Ok, I also have a network bridge to monitor the output of my solar panels, using se-logger

Server:

  • i5 3570 CPU
  • 32 GB of memory
  • Proxmox, hosting a VM for Home Assistant and a VM for some docker containers.

My new setup didn’t need to be way more powerful or larger. For my storage, I have about 800 GB of important storage, and about 1 TB of storage that is less important (actually, when figuring this out, I found out that of that 1 TB more than half of it are Linux ISOs (literally, not air-quote Linux ISOs air-quote…)). The server has CPU power enough, and uses around 16 GB of memory at this moment.

When watching a YouTube video and reading through some forum posts (in Dutch), I came to the conclusion that, when aiming for 10-15 watt idle:

  • your power supply efficiency will be an important factor. A regular ATX power adapter is very inefficient (in that range, sometimes 50% - so doubling your actual power usage). Something like a PicoPSU is almost a requirement.
  • 3.5" disks are a problem: not only when spinning (3-6 watt each), but especially when starting. Sometimes drawing 20 watt each. That limits the possibilities for these DC-DC power supplies.
  • Newer generations of CPUs are way less efficient (12th/13th gen Intel are a no-go).
  • Smaller motherboards with less features are seriously more efficient

In the end, my most important choice is to determine what to do with disks. One/two years ago, when thinking about the successor of my NAS, I was always assuming to increase the disk space, go for 4-6 disks and migrate to something like ZFS. But after making the inventory of the actual disk space needed (not that much…), and the disadvantages from a power perspective of 3.5" disks, I started thinking about SSDs. They are obviously more expensive, but has the time come that it is feasible to use only SSDs in a home-NAS?

Actually, it is, at this moment, 2 TB of SSD is about 100-150 euro, but when it makes the difference between 40 watt, and 20 watt, it saves almost 200 KWh a year, so that is definitely worth it.

Then the puzzle pieces came together, and I started looking for a nice TinyMiniMicro. I finally bought a

  • HP ProDesk 600 G4, with i3 8100T
  • 32 GB of memory (ok, that was maybe not really needed…)
  • WD Black SN770 2TB M.2 SSD
  • Samsung 870QVD 4TB

Maybe I could have gone with less disk space in hindsight, but I also wanted to be done with it for a few years. And, yes, I will not be using RAID / ZFS - when I look at the usage, I can live with a recovery point objective of 1 week or so. So, backups are more important. And for that, I can still use my old NAS. Also, my old NAS can be used as a cold standby. Only time will tell if this was a good decision.

Now, I only need time to install and migrate everything…