Added option and description for nix store auto-optimisation.

1 files changed, 13 insertions, 0 deletions

diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix
index 5088c4e6069..fed646aadac 100644
--- a/nixos/modules/services/misc/nix-daemon.nix
+++ b/nixos/modules/services/misc/nix-daemon.nix
@@ -46,6 +46,7 @@ let
         binary-caches = ${toString cfg.binaryCaches}
         trusted-binary-caches = ${toString cfg.trustedBinaryCaches}
         binary-cache-public-keys = ${toString cfg.binaryCachePublicKeys}
+        auto-optimise-store = ${toString cfg.autoOptimiseStore}
         ${optionalString cfg.requireSignedBinaryCaches ''
           signed-binary-caches = *
         ''}
@@ -86,6 +87,18 @@ in
         '';
       };
 
+      autoOptimiseStore = mkOption {
+        type = types.bool;
+        default = false;
+        example = true;
+        description = ''
+         If set to true, Nix automatically detects files in the store that have
+         identical contents, and replaces them with hard links to a single copy.
+         This saves disk space. If set to false (the default), you can still run
+         nix-store --optimise to get rid of duplicate files.
+        '';
+      };
+
       buildCores = mkOption {
         type = types.int;
         default = 1;