diff --git a/nix/nixos-module/defaults.nix b/nix/nixos-module/defaults.nix
index 2acb012..ced7e74 100644
--- a/nix/nixos-module/defaults.nix
+++ b/nix/nixos-module/defaults.nix
@@ -10,20 +10,29 @@
     };
   };
 
+  documentation = {
+    enable = false;
+    nixos.enable = false;
+  };
+
   environment.systemPackages = with pkgs; [
-    vim screen git wget
+    vim screen git wget psmisc
     tcpdump iputils bridge-utils mtr traceroute
-    dhcpcd
+    dhcpcd ethtool
   ];
 
   networking.hostName = hostName;
 
   users.users.root.initialHashedPassword = "";
 
+  # for vm-packages
   virtualisation = lib.optionalAttrs (builtins.hasAttr "qemu" options.virtualisation) {
-    memorySize = 4096;
+    memorySize = 8192;
     msize = 65536;
     cores = 4;
+    diskSize = 8192;
+    writableStore = true;
+    writableStoreUseTmpfs = false;
     qemu.options = [ "-enable-kvm" ];
   };