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Disk swap is not extra RAM

A huge disk swapfile delays OOM and can hang a headless box; prefer small zram plus kill/evict

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Swap is spill, not capacity. Pages come back 100–1000× slower than RAM. A large disk swapfile lets the kernel thrash (SSD busy, allocators stall, NIC/watchdog look dead) instead of killing a fat process.

On a small always-on Linux box (k8s + DB + agents):

  • Prefer 2–4 GiB zram (compressed, memory-speed) for short spikes.
  • Do not add a swapfile ≥ RAM on the same NVMe as the OS/DB.
  • Pair with earlyoom / kubelet eviction that fire while swap still exists. Huge swap delays that signal.

More swap is useful for hibernate or parking idle desktops. It is a trap when the working set already exceeds RAM and the host must stay reachable.

Related: user-duyet-homelab (keep topology out of kb — feedback-public-kb-only).

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