Every five years I rebuild my FreeNAS file server by replacing old hardware with new hardware. One component that I always toss out after running 24/7 for five years is the case fans. For the 2015 rebuild, I had Deepcool 120mm fans in front, NZXT 120mm fans in back and bottom, and a pair of Apevia 140mm fans at top. There’s nothing special about these fans except for the bottom fan, where air circulation is needed to avoid overheating the hard drives. The regular 120mm fan was 25mm thick and blocked the bottom drive bay. Not a problem when I only had six hard drives. For the 2020 rebuild, I added two new hard drives and needed all eight drive bays. How can I have a fan and a hard drive occupy the same space at the same time?

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The solution was the SilverStone Slim 120mm fan for $14 USD each that is 15mm thick (or 10mm thinner than a regular case fan). I used the included anti-vibration rubber mounts to attach the slim fan to the case to blow the hot air out. The other problem I had with the bottom fan was the power and SATA cables interfering with the fan, if I wasn’t careful putting the side panel back on.

That problem fixed itself when I replaced the non-modular power supply with a modular power supply, needing only the mainboard and hard drive power cables. By switching the hard drives from the mainboard to the SAS controller card, the SAS-to-SATA breakout cables also reduced the cable clutter over the bottom fan. I still wanted a finger grill on the top of the slim fan to prevent my fat fingers from interfering with the fan.

Adding the finger grill created another problem by blocking the hard drive from going into the bottom drive bay. I had to cut out the first three rails of the finger grill to accommodate the bottom edge of the hard drive that sits on top of the slim fan. If I was to replace the bottom hard drive, I would have to remove the hard drive above it to have extra wiggle room to clear the finger grill.

Since I added a SAS controller card for this rebuild, they tend to run hot at 120F or 49C. If I ever add a 10Gb network card, it’ll run just as hot. The case does have a 120mm or 140mm fan mount on the side panel that is directly above the expansion cards. I mounted another slim fan with a finger grill to blow air into the case, using the included screws to attach the fan with a dust filter in between it and the side panel. I plugged the ketchup-and-mustard power cable into a three-pin extension cable to provide extra length when removing the side panel. The side-mounted fan reduced the temperature of the SAS controller card by ten percent. 

As for all the other case fans, I have three Arctic F12 PWM 120mm fans in front and back, and a pair of Arctic F14 Silent 140mm fans at top. Unlike the SilverStone slim fan, the Arctic fans have black power cables. These fans are quite affordable when rebuilding multiple systems.

Since the mainboard has only two fan headers, I added a pair of Deepcool fan controller hubs for $9 USD each. One hub plugs into the CPU fan header for the four-pin CPU cooler and Arctic 120mm fans. The other hub plugs into the system fan header for the three-pin Arctic 140mm fans and SilverStone 120mm fans. I added three- and four-pin extension cables where needed for better cable management.

What about the temperatures? My home office is a constant 80F or 27C, give or take a few degrees. The external case temperature is a few degrees higher than room temperature. The hard drives are a few degrees higher than the external case temperature. Those temperatures are no different than the previous build. The total cost of replacing all my case fans came to about $100 USD.