From af3224a1d589aef9ca326202d8ca6c4ee5a3882a Mon Sep 17 00:00:00 2001
From: Swarsel <leon.schwarzaeugl@gmail.com>
Date: Thu, 11 Jul 2024 11:08:22 +0200
Subject: [PATCH] feat: add NixOS auto-GC and -store optimisation

---
 SwarselSystems.org        | 27 +++++++++++++++++++++++++++
 profiles/common/nixos.nix | 12 ++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/SwarselSystems.org b/SwarselSystems.org
index 8962572..2b84fb1 100644
--- a/SwarselSystems.org
+++ b/SwarselSystems.org
@@ -4660,6 +4660,33 @@ Needed for control over system-wide privileges etc.
 
 #+end_src
 
+**** Enable automatic garbage collection
+
+The nix store fills up over time, until =/boot/efi= is filled. This snippet cleans it automatically on a weekly basis.
+
+#+begin_src nix :tangle profiles/common/nixos.nix
+
+  nix.gc = {
+    automatic = true;
+    randomizedDelaySec = "14m";
+    dates = "weekly";
+    options = "--delete-older-than 10d";
+  };
+
+#+end_src
+
+**** Enable automatic store optimisation
+
+This enables hardlinking identical files in the nix store, to save on disk space. I have read this incurs a significant I/O overhead, I need to keep an eye on this.
+
+#+begin_src nix :tangle profiles/common/nixos.nix
+
+  nix.optimise = {
+    automatic = true;
+    dates = [ "weekly" ];
+  };
+
+#+end_src
 
 **** Reduce systemd timeouts
 :PROPERTIES:
diff --git a/profiles/common/nixos.nix b/profiles/common/nixos.nix
index 830730f..1e1042b 100644
--- a/profiles/common/nixos.nix
+++ b/profiles/common/nixos.nix
@@ -32,6 +32,18 @@ stylix.targets.grub.enable = false; # the styling makes grub more ugly
 
 security.polkit.enable = true;
 
+nix.gc = {
+  automatic = true;
+  randomizedDelaySec = "14m";
+  dates = "weekly";
+  options = "--delete-older-than 10d";
+};
+
+nix.optimise = {
+  automatic = true;
+  dates = [ "weekly" ];
+};
+
 # systemd
   systemd.extraConfig = ''
   DefaultTimeoutStartSec=60s