Swap, ZRAM, Zswap and Hibernate on NixOS

I pulled this out of my non-obvious nixos config piece into its own post. On this page Oh no, I'm going to talk about swap, zram, zswap... Whether to use swap is a perennial fight online. The conversation is often muddled when people conflate recommendations for servers with recommendations for workstations. In my case, I'm going to focus on desktops and laptops. I use swap because I like suspend-then-hibernate, or "Standby, then hibernate" in the KDE settings: ![[Pasted image 20260917120542.png]] This will first ACPI S3 suspend to RAM, then after a delay go into S4 Hibernate. I think this strikes a nice balance: if I step away for a bit I don't have to wait for things to start up, but I don't have to worry if I forget to fully power off my machine. To use hibernate you need swap to save your system state to disk. Let's add even more fuel to the fire There are also arguments over swap files vs swap partitions. I mostly want to note that swap files can complicate hibernate. That is…