From 82c53e2c5c23ccd4fb2c24511084f7a828a20731 Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Sun, 13 Mar 2022 17:13:27 -0600
Subject: Add snapper

---
 sys/default.nix | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

(limited to 'sys')

diff --git a/sys/default.nix b/sys/default.nix
index c68c869..3840a30 100644
--- a/sys/default.nix
+++ b/sys/default.nix
@@ -35,6 +35,11 @@ in {
       type = listOf str;
     };
 
+    snapperSubvols = mkOption {
+      type = attrsOf str;
+      default = {};
+    };
+
     crypt = mkOption {
       type = submodule {
         options = {
@@ -327,6 +332,65 @@ in {
       ];
     };
 
+    local.snapperSubvols.home = "/home";
+
+    services.snapper.configs = let
+      snapperConfig = _: subvolume: {
+        inherit subvolume;
+
+        extraConfig = ''
+          # btrfs qgroup for space aware cleanup algorithms
+          QGROUP=""
+
+          # fraction of the filesystems space the snapshots may use
+          SPACE_LIMIT="0.5"
+
+          # fraction of the filesystems space that should be free
+          FREE_LIMIT="0.2"
+
+          # users and groups allowed to work with config
+          ALLOW_USERS=""
+          ALLOW_GROUPS=""
+
+          # sync users and groups from ALLOW_USERS and ALLOW_GROUPS to .snapshots
+          # directory
+          SYNC_ACL="no"
+
+          # start comparing pre- and post-snapshot in background after creating
+          # post-snapshot
+          BACKGROUND_COMPARISON="yes"
+
+          # run daily number cleanup
+          NUMBER_CLEANUP="yes"
+
+          # limit for number cleanup
+          NUMBER_MIN_AGE="1800"
+          NUMBER_LIMIT="100"
+          NUMBER_LIMIT_IMPORTANT="10"
+
+          # create hourly snapshots
+          TIMELINE_CREATE="yes"
+
+          # cleanup hourly snapshots after some time
+          TIMELINE_CLEANUP="yes"
+
+          # limits for timeline cleanup
+          TIMELINE_MIN_AGE="1800"
+          TIMELINE_LIMIT_HOURLY="24"
+          TIMELINE_LIMIT_DAILY="7"
+          TIMELINE_LIMIT_WEEKLY="4"
+          TIMELINE_LIMIT_MONTHLY="12"
+          TIMELINE_LIMIT_YEARLY="10"
+
+          # cleanup empty pre-post-pairs
+          EMPTY_PRE_POST_CLEANUP="yes"
+
+          # limits for empty pre-post-pair cleanup
+          EMPTY_PRE_POST_MIN_AGE="1800"
+        '';
+      };
+    in mapAttrs snapperConfig cfg.snapperSubvols;
+
     networking.firewall.allowedTCPPorts = [ 2234 ];
 
     programs = {
-- 
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