I just wanted my homelab to run smoothly. But sometimes, the universe (and Linux) has other plans.
\nMy home server hosts a bunch of small things on my old hardware.
\nIt connects via Wi-Fi, because i didn’t want to run a 20-meter Ethernet cable halfway across the house to where my router is.
\nSo… I stuck with Wi-Fi.
\nLittle did i know, the trouble it would cause.
\nEvery once in a while, my entire system would just freeze.
\nNo response, no errors, no log, no warning. Just fans spinning and the little lights blinking.
\nThe only way to bring it back? Pull the plug.
\nAt first, I thought I was overloading it. Maybe too many containers, maybe overheating, maybe the RAM.
\nMy mind was saying “it’s probably hardware”.
\nIt wasn’t until a few nights ago, when it crashed again mid-session, I decided to dig in.
\nsyslog and journalctl didn’t give me anything obvious.
That’s when I asked ChatGPT to pair-debug with me, and together we started narrowing things down.
\nAfter a bit of back-and-forth, we found something interesting buried in dmesg:
iwlwifi 0000:02:00.0: Device error - SW reset\niwlwifi 0000:02:00.0: Start IWL Event Log Dump: nothing in logI thought it was supposed to “just work”.
\nMaybe with a little less throughput (no ethernet remember).
\nApparently, under high system load, Intel Wi-Fi chips can panic, crash the firmware, and sometimes freeze the entire system.
\nTurns out, the issue comes from aggressive power-saving and hardware crypto settings that don’t play nicely under load.
\nThe fix was to offload some stuff from the Wi-Fi driver (iwlwifi).
I added a few lines to /etc/modprobe.d/iwlwifi.conf:
options iwlwifi power_save=0\noptions iwlwifi 11n_disable=8\noptions iwlwifi swcrypto=1and ofc, i didn’t know what these do, so after finding out, here is what these do
\npower_save=0: disables Wi-Fi power-saving features (like periodic sleep modes).
11n_disable=8: disables A-MPDU aggregation, a feature that batches multiple pkts/frames into one large transmission.
The Catch:
\nswcrypto=1: forces encryption/decryption of Wi-Fi traffic to happen in software (CPU) rather than the card’s onboard hardware
The Catch/Win:
\nTo see if it actually worked, I wanted to stress test it, which is where i found stress-ng.
I started with individual components test (for ~10mins each)
\n# cpu\nsudo stress-ng --cpu 8 --timeout 600s --metrics-brief \n# ram\nsudo stress-ng --vm 2 --vm-bytes 80% --timeout 600s --metrics-brief \n# disk, careful it can corrupt the disk\nsudo stress-ng --hdd 2 --hdd-opts dsync --timeout 600s --metrics-brief\n# i/o\nsudo stress-ng --io 2 --timeout 600s --metrics-brief# sends pkts as fast as the network allows\nsudo ping -f -s 1400 google.com sudo stress-ng --cpu 4 --vm 2 --vm-bytes 70% --hdd 1 --io 2 --timeout 600s --metrics-brief\n# plus Wi-Fi module stress in parallel\nsudo ping -f -s 1400 google.com This time… nothing crashed.
\nNo hangs, no lag, no freeze, just some fan noise.
\nI was happy, my server handled it, and most importantly it was still working fine.
\nBefore this, I never really thought about Wi-Fi drivers at the kernel level.
\nBut this bug made me realize how deep Linux’s stability goes - and how fragile things can get when firmware starts misbehaving.
\nAnd the irony is, if I had just used Ethernet, I would’ve never even discovered this.
\nAvoiding “the easy fix” lead me to a much better one.
\nRunning a homelab, among many things, also helps to understand how these system behaves under pressure.
\nIn my case, it helped me uncover and fix a bug that I didn’t even know existed.
\nTechnically, all bugs are like this when they are first discovered, but this bug especially was not on my bingo cards.
\nAll this, just because I didn’t want to run an Ethernet cable - but honestly, I’m glad I didn’t.
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