ZFS based NAS and home lab [Silencer Box]

This is the third part of my 'ZFS based NAS and home lab' series. The first part concentrated on why i am doing it and the second part was about the servers hardware configuration.

In this part i want to describe my silencer box which i built to actually run the server next to my desk.



As i already said before in this series a 19" server is not built to sit next to your desk, it's build to live in the server room where you have cooling and noise is irrelevant. The silencer box has to reduce the sound down to something acceptable but it as well has to guarantee that enough air gets in to cool the server.

I was not sure if it will work out but in the end it worked well enough. In standard use, more or less idle, the sound level is about the same as my Desktop, if i put some real load on though (running packer builds, bigger compiles,...) it does not really reach that level. This is mainly as the internal fans will spin up to get the temperature below 35 °C on this Dell R710, in idle or base usage the fans are down at 3600 rpm but then they go up to >8k rpm and that is definitely loud. So far i did not find a way to tweak the fan controller to spin up at higher temperatures which would be the ideal fix. A Xenon CPU will be fine up to 70°C so it would be great to stay at silent rpms until at least 40°C.
Oh well maybe i find a fix for that at some point but for my need it's acceptable.

Let's dive into the box design.
I decided to go with a frame structure that will hold the server and then add wood panels for a nice look and to hold the insulation.

I "constructed" the box via FreeCAD so if you want to build something like that or just want to have a more detailed look fetch this file and open it up. Feel free to use and modify as you like.

On these pictures you see the frame construction and how the server is intended to stand in it.

That frame holds the wood panels and on those i have added 4cm thick compounded foam which is actually quite heavy. To use a heavy thick foam instead of some "acoustic" pyramid foam has the advantage that a thicker, denser material is able to reduce noise a lot better - it's more expensive though.

This picture shows the server standing in the case with the insulation already in.

The idea in the arrangement is that i have a split airflow for intake and exhaust. In these pictures i had 2 80mm fans in the exhaust which i changed to one for intake and one exhaust. This arrangement provides actually better airflow and lower temperatures in the case.



Here you see the air channel from a closer perspective.

If your server is running a higher workload consider to make these bigger to get more air in and out of the case. Maybe as well add 2 more fans, i just wanted to start with 2 and see if it's enough.

The fans get their power independent from the server as i needed 12V and there was no nice way to get those out easily. It can be done obviously but i did want to keep the server basically untouched. The power for the fans comes from a little LED power supply as that gives a stable 12V and is cheap as i just need enough for 2-4 fans which is 4-5W at max.
What i changed in the server though is that i added a small piece of wood into the intrusion detection switch so it never reports an open case. I have the server in as you see it on the pictures, without the top cover. This way the noise of the fans goes directly against the foam and i got a few more dbs down.

The next pics show the closed case. I used beech wood and applied some layers of coating to get a nice surface. That took most of the build time as you apply a layer, let it dry for a day, grind it and repeat.

The box is pretty high with close to 1m but it works nice next to my desk :) 

I did some measurements with a noise measuring app on my phone. Not sure how realistic the measurements are but without the case the servers idle noise was around 50db. The app thinks that this is roughly conversation noise level but from the server it's a constant noise you don't want to have next to your desk.

The box brought that down to around 20db which has nothing to do with a really silent PC but it's acceptable and the insulation led to less annoying frequencies. It's not a noise i want to sleep next to but it can easily be ignored while working, especially if you have music running as i usually do.

Ok this was part 3 of the 'ZFS based NAS and home lab' series. 

The next part will cover what i actually run on the server and how that plays out.

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Part 1: ZFS based NAS and home lab [Intro]

Part 2: ZFS based NAS and home lab [build] 

Part 3: ZFS based NAS and home lab [silencer box] (this page)