diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index a8db42f5ed6f..6ce4461babc7 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -318,7 +318,7 @@ in
     virtualisation.diskSize =
       mkOption {
         type = types.nullOr types.ints.positive;
-        default = 512;
+        default = 1024;
         description =
           ''
             The disk size in megabytes of the virtual machine.