modules/disks: Setup a tmpfs for the new lix build location

Otherwise, builds are performed on-disk.

1 files changed, 11 insertions, 2 deletions

diff --git a/modules/by-name/di/disks/module.nix b/modules/by-name/di/disks/module.nix
index d88fa3df..d5746ecf 100644
--- a/modules/by-name/di/disks/module.nix
+++ b/modules/by-name/di/disks/module.nix
@@ -109,11 +109,20 @@ in {
       nodev = {
         "/" = {
           fsType = "tmpfs";
-          mountOptions = ["defaults" "size=4G" "mode=755"];
+          mountOptions = ["defaults" "size=25%" "mode=0755"];
         };
         "/tmp" = {
           fsType = "tmpfs";
-          mountOptions = ["defaults" "size=16G" "mode=755"];
+          mountOptions = ["defaults" "size=50%" "mode=0755"];
+        };
+        "/nix/var/nix/builds" = {
+          fsType = "tmpfs";
+          mountOptions = [
+            "defaults"
+            "noswap" # Otherwise, we might run into io-based slowdowns
+            "size=75%"
+            "mode=0755"
+          ];
         };
       };
     };