diff --git a/nixos/modules/virtualisation/docker.nix b/nixos/modules/virtualisation/docker.nix
index 7288cf29875b..0c642bf3b816 100644
--- a/nixos/modules/virtualisation/docker.nix
+++ b/nixos/modules/virtualisation/docker.nix
@@ -46,12 +46,10 @@ in
     storageDriver =
       mkOption {
         type = types.enum ["aufs" "btrfs" "devicemapper" "overlay" "zfs"];
+        default = "devicemapper";
         description =
           ''
             This option determines which Docker storage driver to use.
-            It is required but lacks a default value as its most
-            suitable value will depend the filesystems available on the
-            host.
           '';
       };
     extraOptions =
diff --git a/nixos/tests/docker.nix b/nixos/tests/docker.nix
index 034dcb04adfd..635a97e2ce09 100644
--- a/nixos/tests/docker.nix
+++ b/nixos/tests/docker.nix
@@ -11,6 +11,8 @@ import ./make-test.nix ({ pkgs, ...} : {
       { config, pkgs, ... }:
         {
           virtualisation.docker.enable = true;
+          # FIXME: The default "devicemapper" storageDriver fails in NixOS VM
+          # tests.
           virtualisation.docker.storageDriver = "overlay";
         };
     };