I fixed a server with a precisely placed piece of tape (2023)
social.treehouse.systems
social.treehouse.systems
Unless the work to be done is unlimited, all else being equal, hopefully a well functioning system puts out less heat to do X amount of work than a poorly running system.
I feel like that might be embedding some questionable assumptions, such as:
1. That CPU computing work completed is directly proportional to joules of heat emitted.
2. That stymied active cooling measures don't themselves generate heat, such as all the fan motors spinning at 100% and the AC/DC conversion to power them.
3. That even if performance was improved by removing thermal-throttling, demand would still push everything to run at full-tilt rather than allowing some machines to idle.
...I'm pretty surprised these systems booted at all without CPU coolers?
I did one of these in the early naughts. Something like half a rack of old pentium 2-3 era boxes running non-prod — back office, network share storage, dev, staging — to a single beefy server running some flavor of vmware. We had all the older gen hardware for isolation and convenience, not because we needed the compute so I specced a “big” box that could hold a lot of storage (for the time) and performance was a non-issue. I think I also saved a lot on Microsoft licensing which made budget for the hardware.
About a year later we were rearranging some stuff and someone powered it off and picked it up to move it… and heard a rattle inside. Pop the cover off and the CPU cooler is sitting in the bottom of the case and the CPU is just sitting there naked. Had absolutely no problem running without the fan at all. We clipped it back on anyway just to be safe :)
There are also comments that claim to have done this (the oldest I saw was a Q8200, and someone said a 3000G could be run indefinitely without a heatsink).
https://www.youtube.com/watch?v=tU9yjwMlbRI (Ryzen 3000)
https://www.youtube.com/watch?v=ycIF1NDkW6M (Pentium G5400)
I frankly don't believe GP's story, I think GP must be misremembering this detail.
So, yep, CPUs - at least 2014-vintage Intel Core i5s - can run surprisingly well without cooling!
Why would they take hours? Something something about energy consumption (and heat) growing to the square of the clock speed. You take a server that can go to, say, 3.2 Ghz and limit it to, say, 0.8 Ghz, it's going to be cool to the touch. And at 25% the speed, something taking ms or seconds, won't suddenly take hours.
That's why nobody noticed: because they didn't take hours neither to boot nor to do something.
Thermal throttling. I have personal experience with that: once I received a laptop which was missing the four screws holding the heatsink. It took over half an hour trying to boot Windows before powering down due to overheating. Since I'm not used to Windows, I thought it being very slow (on the first boot, which sets things up) might be normal, but suddenly powering down certainly wasn't, and the BIOS event log pointed to the culprit.
The issue is that AFAIK it does not reduce the clock rate; it runs at the normal full clock rate, then when it detects the temperature went over the limit, it pauses the CPU for a while to let it cool down. With a missing CPU fan, that might be enough, but it wasn't enough with the heatsink detached.
> That's why nobody noticed: because they didn't take hours neither to boot nor to do something.
It's normal for servers to take a while to boot (before even getting to the operating system).
I'm 99% confident that that is not a thing, pausing the cpu. The closest thing that exists is sleep/suspend/hibernate, but those don't work like that (on temperature triggers). Other than those, if the machine is on: the cpu is always doing _something_.
That used to be the case back in the 1990s when running MS-DOS. Nowadays, every operating system "pauses" the CPU when nothing is going on. The traditional way on x86 was to use the HLT instruction, which stops the processor until an interrupt happens; other architectures have their own equivalents (for instance, ARM has the WFI and WFE instructions), and x86 has more modern ways to do the same thing (like the MONITOR/MWAIT instructions). These instructions allow the processor to dynamically enter lower power modes, for instance by blocking the clock and/or power going into parts of the processor core (that is, "gating" the clock or power).
Maybe I'm wrong, looking back at what I said I'm having a hard time explaining what my objection is, but I just don't know of a mechanism that's like "welp, I'm too hot, pausing for a few seconds, see you then!". Aren't there buses and caches and etc. that need constant attention whenever the machine is on? The cpu can't just tell everything to wait for a bit.
Some people really like dedicated single function hardware, they might have been putting a micro service on each one
One day it stopped working. During troubleshooting it would work only on a 10 year old PC I had lying around. The difference? Despite being full-size, the GPU slot on the old mobo was wired only for x8.
I reckon that the GPU die lost connection on some pins. Not worth fixing, x8 works fine.
Then I discovered that putting tape on my mouse's USB receiver interfered with the wireless connection.
Then I got a USB hard drive which has an LED along the top left corner, where tape won't stick.
Then I got a microwave which always displays the time when it's not in use, and if I cover up that display, I can't see the timer for my food.
And somewhere around there I gave up. It was impossible to tell before buying these products that they would come with lights, no one talks about this!
Maybe at Fry‘s they had the microwaves plugged in? I don’t remember.
Obviously not viable for evaluating continued operation for something like a fridge, but just turning it on for the panels is usually possible.
Be sure to buy from the original family business, not the knockoffs.
I don't need my house to look like a fucking carnival. Who does this appeal to?
As the comments say:
> Now waiting for the war story from your successor "you'll never guess what I found when I took apart this one server that wouldn't wake-on-lan"
If the thing is broken because X then you can fix it by removing X. That's enough explanation. You don't need to know "why" for everything.
But if disabling a faulty connection you don't need in the first place stops the problem happening, that's a decent workaround... I'd just be a little worried that something else could be faulty on the card if the WoL pin is glitching, so potentially you could have other intermittent issues.
Maybe that's good enough for them, people never touch this problem again, and we wouldn't have this story (which of course would be sad). But it occurs to me that the author wasn't in a rush to fix this and had plenty of time to poke around. I wish I could do that.