diff --git a/pkgs/by-name/md/mdadm4/package.nix b/pkgs/by-name/md/mdadm4/package.nix
index d5cb54bc0766..7a33badb3d03 100644
--- a/pkgs/by-name/md/mdadm4/package.nix
+++ b/pkgs/by-name/md/mdadm4/package.nix
@@ -43,7 +43,7 @@ stdenv.mkDerivation rec {
     "INSTALL=install"
     "BINDIR=$(out)/sbin"
     "SYSTEMD_DIR=$(out)/lib/systemd/system"
-    "MANDIR=$(out)/share/man"
+    "MANDIR=$(man)/share/man"
     "RUN_DIR=/dev/.mdadm"
     "STRIP="
   ]
@@ -51,6 +51,11 @@ stdenv.mkDerivation rec {
     "CROSS_COMPILE=${stdenv.cc.targetPrefix}"
   ];
 
+  outputs = [
+    "out"
+    "man"
+  ];
+
   installFlags = [ "install-systemd" ];
 
   enableParallelBuilding = true;