A few months ago, I did a post about my plan to upgrade my server rack. A user with the sweet sounding name of @dauerstaender requested a follow up, so here we are.

Open bottom and fans

As mentioned in the original post, a huge point was the open bottom. Together with my pops, I made a piece of plywood to seal off the hole and to mount four 120mm fans with dust filters.

![Open bottom][1]

![Plywood board][2]

![Plywood board in server rack][3]

![Plywood board in server rack with fans][4]

I used Noctua's NF-P12 redux-1300 PWM fans. They are dead silent on medium-low speed, support PWM signals between 0.0 (off) and 1.0 (full speed), have Noctua's high quality standards, and are quite affordable for a 4-pin PWM fan with roughly 14.50 € (15.88$) each.

The two holes in the back are for in and outgoing cables but as there are only a couple of cables that have to be led outside I kept them quite small.

Instead of magnetic strips, I just used the screws that I took to fasten the fans for the dust filters as well.

![Plywood board from the bottom][5]

I also swapped the old 80mm 3-pin chassis fans of my server for 4-pin PWM fans from the Noctua redux-series and tweaked the fan curve a bit. I will have to do this again when I move as the server is at the attic right now and it is winter here.

![Server fans][6]

The plywood board and fan swapped alone helped a lot to reduce noise. Right now, the server rack produce less noise then my work laptop when it is under medium load...

Fan controller

After some baby steps by getting used with my power supply and wiring up a single fan, I managed to implement a temperature sensor, a level shifter to raise the 3.3V PWM signal from the Pi to a 5V signal which the fan expects, and a circuit to read the RPM on the open collector (never heard that term before...) of the third pin of the fan.

![Baby steps][7] ![Baby steps 2][8] ![Baby steps 3][9] ![Finished baby steps][10]

The code for the controller and some further information can be found here.

Here is the final temporary solution as it currently hangs in my server rack.

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It also has a function to export data via Prometheus to Grafana to monitor the temperature and fan speed.

Sound proofing

As of now, the quieter fans and the plywood board suffice but in the end I will use something like Basotect to clad the inner sides of the rack and to seal of the cable ducts. But that will wait until I have everything else done.

Outlook

As mentioned in the repository, I want to learn to design a PCB with a everything on it to ditch the breadboard, additional circuitry, fan hub, etc. I already did some research and it seems quite possible that I am able to do that. But that will take some time :D Afterwards, I will design a printable case to make it look a bit slicker.

And I have to fix a bug in my script. Quite randomly, the fan controller spin up all fans to maximum speed for one cycle (30 seconds) and I don't know why, yet...

![Grafana][11]

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All in all, it is really a fun project although I had to learn quite a lot for it but Linux, and genuinely basic Python and electronics.

If you want to know more feel free to look into my repo, drop a message or comment. Also, I appreciate any hint or help :)

[1]: https://feddit.de/pictrs/image/649d83aa-fa3b-4b4a-baf6-fb8283b28876.jpeg [2]: https://feddit.de/pictrs/image/be605913-9dfe-44e8-bec6-438ec667a80d.jpeg [3]: https://feddit.de/pictrs/image/94883068-40f8-44c1-b3df-6e882b170254.jpeg [4]: https://feddit.de/pictrs/image/2f0a5c10-1874-4f57-803a-d6856805965e.jpeg [5]: https://feddit.de/pictrs/image/a5e0e4e7-25ba-4d67-bf61-f7becbcf57cc.jpeg [6]: https://feddit.de/pictrs/image/9baa0462-08c9-489a-9ec7-5df482243b05.jpeg [7]: https://feddit.de/pictrs/image/c93e0d8e-a3ff-467f-a87f-5bc92a28f978.jpeg [8]: https://feddit.de/pictrs/image/bd6a613b-0f49-43d6-b1d9-32ffab1c24ef.jpeg [9]: https://feddit.de/pictrs/image/eb8b7be7-ed65-4586-ad8e-10893b412599.jpeg [10]: https://feddit.de/pictrs/image/6ce374d5-2ff3-474c-9964-af642488f489.jpeg [11]: https://feddit.de/pictrs/image/6d1585aa-cf46-4fc2-adf6-4f1d42f9779e.png

Hello :)

If you don't want to read everything just jump to the target state/help section below :)

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Introduction

Roughly a year ago, I got my hands on a used but good quality 20U server cabinet. Since then, despite containing my running home server and my network gear, it remained in a quite unfinished state on my parent's attic. In the near future, it could appear that I have to share my home office/gaming room with it (so several hours a day). Therefore, I would like to implement proper sound (and dust) proofing measurements and cooling. Sadly, I am not that knowledgeable about server hardware and accessory yet, so I seek help here :)

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Current state

Right now, the cabinet contains the following devices:

• Router/modem (passively cooled)
• Managed switch (passively cooled)
• Home server with four hard disks running all my services

The bottom is open.

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On top, there are four mounting slots for 120mm fans. Currently, just one is installed and not being used.

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On top and at the bottom in the rear area, there are openings for the in- and outgoing cables which are not covered at the moment. They are 52 cm wide.

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Target state/help

(It might be important for availability of parts or material: I am in Germany.)

Devices

In the future, the cabinet should contain the following devices:

• Old router as modem (passively cooled)
• Dedicated router/firewall device (OPNsense/pfsense, passively cooled)
• Managed switch (passively cooled)
• At least four clustered thin clients (I have four Fujitsu Futro S920 lying around, passively cooled)
• Dedicated file server with at least twelve hard disks (actively cooled)
• UPS

I assume only the file server will generate noticeable noise while the rest will generate only heat.

Open bottom

For the open bottom I assume a plain plywood board with openings for four 4-pin 120mm fans (or two bigger fans - less RPM, less noise?) as intakes and magnetic strips at the bottom for dust filters will suffice, am I correct there? Are there better alternatives?

Top fans

For the top, I would install four 4-pin 120mm fans as exhausts. Do you have recommendations for these? Else I would go for known brands as Noctua or bequiet! and compare noise levels.

Fan controller

I have to admit that I never had a fan controller in my hands and have little knowledge about them. Do you have recommendations for a controller for six or eight 4-pin fans? As I looked them up online, I mostly found controller which seems to be intended for desktops, not server cabinets. And when i got one, do I put it on a shelf in the server cabinet or could I mount it on a rail on the side of the cabinet?

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Cable ducts

I am completely clueless how covers for these cable ducts are properly called. I looked up several combinations of the words "dust", "cover", "server", "cable", and so on and didn't find what I was looking for. As mentioned above, the ducts are roughly 52x6cm. As I got the cabinet, there were pretty nasty foaming and glue residue which I had to scrub off. Are there covers with bristles or foaming to cut into the right size that that help against dust and noise?

Further sound proofing

Would it be a good idea to sound proof the inner sides with some kind of padding or other kind of non-flammable sound damping insulation material?

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Sorry for the long post! I appreciate every hint and tip :)

Have a great day!