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Comment by thetanil | Hacker News Reader

Running a 6 node cluster of Pi4s at home now. Did some benchmarks. Long story short.

USB thumb drive boot disks are better performance and cheaper than SD cards.

Fans are completely unnecessary on a Pi4 with an aluminum heat shield style "case". They do run hotter than with a fan, but they will not be heat throttled with recent firmware.

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Some usb drives are much slower than a decent sd card. Also, the ultra has cooling issues.

However, there are usb3 nvme enclosures that are incredibly cheap, and blow both out of the water:

https://www.jeffgeerling.com/blog/2020/fastest-usb-storage-o...

For a build like the one in the article, I imagine something that puts two nvme sticks beside each other, sandwiched between every other rpi, with passive aluminum heat shields in the remainder of the spaces between the rpi’s. I bet it could be even denser (more pis and more storage) and quieter.

I wonder if space can be saved by making a heat shield heatsink that has a pi on both sides, and fins in the middle.

Super cool article.

Yeah, I recently spied the 4 node Jetson Mate carrier board on CNX that facilitates building your own Multi GPU cluster ;)

https://www.seeedstudio.com/Jetson-Mate-Cooling-Kit-p-4784.h...

They recommend Kubernetes for private cloud workloads. But I am wondering if there isn't room in the ecosystem for a new virtualization / containerization technology to orchestrate tasks on multi gpus? Have heard NVidia is developing its own OS, or rather two, one for Cloud AI and one for real time robotics, but its still research phase...

That's a slick cluster in a box. I'm not sure which modules I'd put on it, though. Unless you harvest them from the 2 GB dev kits, the total price pushes up against a single Jetson Xavier AGX, which is a better value (and has an M.2 slot for an SSD).

yeah, I'm excited to get my hands on some Jetsons too. the 4gb memory on the pi is really a big pro though. when one of these SBCs finally comes with 8GB and GPU acceleration for < 100$ we will see some real progress I think.

> when one of these SBCs finally comes with 8GB and GPU acceleration for < 100$ (...)

It might have GPU acceleration but the RPi already comes with 8GB of RAM for about 80$.

https://www.raspberrypi.org/blog/8gb-raspberry-pi-4-on-sale-...

Pi comes with 8gb ram now

Example case which does away with the need for fans is:

https://www.amazon.com/Geekworm-Raspberry-Computer-Aluminum-...

I've been using the FLIRC case, which appears to be die-cast and looks a little bit more family friendly sitting next to the TV on your entertainment center.

https://flirc.tv/more/raspberry-pi-4-case https://flirc.tv/more/raspberry-pi-case (for RPi 2 and 3)

I like this one, a little more expensive but makes the Pi into a NUC style SFFPC:

https://www.waveshare.com/pi4-case-argon-one.htm

Edit to add the fan is optional, so it can run fanless with no throttling.

looks cool, and the breakout board is nice, but they don't show how it attaches to the pi. it's aluminum yeah, but does it actually do anything for heat dissipation?

Scroll down that page, there’s a photo and description... “The Extension Pillars Makes The Aluminum Case Become A Big Heatsink”

That’s good value with the 2 hdmi adapters

I use one of those for my headless dedicated Pi4B website server plus UPS controller.

Admittedly, that's a simple load, but my Pi never gets over 42 degrees C, in a tropical area, averaging around 30 degrees C.

>Fans are completely unnecessary on a Pi4 with an aluminum heat shield style "case". They do run hotter than with a fan, but they will not be heat throttled with recent firmware.

1 x 4k@60hz with no case and alu heat shield and my RPI4 does throttle. Latest firmware. Seems you don't punish it enough.

That's the GPU which I would expect to be fairly idle on a cluster of any sort unless you're doing GPU computing (and then why are you using a Pi?)

I used the following case/setup and can confirm. No fans are required and booting is lightning fast. https://www.prusaprinters.org/prints/40852-pi4-case-stand

USB isn't very good for high vibration environments (e.g. inside robots) though :-/ Worst abomination of a connector design I've seen in a couple decades. I wish they had locking industrial connectors on the USB ports on the Pi ... although a SATA/m.2 would be nicer.

I guess that's why you'd move to the compute module?

Does a little drop of glue fix the issue, or is there something else?

Not really, because that makes it really hard to unplug/replug for servicing.

I wish USB was designed to at least snugly support housing to housing of connectors and not have the entire connector supported by a flimsy piece of sheet metal soldered to a PCB.

Which USB thumb drives and which SD cards?

Do you overclock?

If you ran at 99-100% CPU on average, would you still not need fans?

any usb 3.0 drive works, but I am using SanDisk Ultra Fits. price per byte is less and performance is similar or slightly better for reads and way better for sustained writes.

No Overclock.

99-100% CPU on all 4 cores for hours and no throttling. they do run at 75-78C instead of 65C, but I could not get them to throttle.

Even with the cheapo 3 piece heat sinks there was almost no throttling, but they did throttle occasionally after sustained stress.

missed the SD cards. I am benchmarking against the best SD cards I can get because that is always the bottleneck on the Pi to my experience. The bandwidth and clock rate on USB3 vs sdcard bridge is just faster, but the media is also cheaper in USB3 format in general.

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