diff --git a/pkgs/servers/nosql/mongodb/default.nix b/pkgs/servers/nosql/mongodb/default.nix
index ee373878cb62..11720fb154fb 100644
--- a/pkgs/servers/nosql/mongodb/default.nix
+++ b/pkgs/servers/nosql/mongodb/default.nix
@@ -7,7 +7,7 @@
 
 with stdenv.lib;
 
-let version = "3.2.9";
+let version = "3.4.2";
     system-libraries = [
       "pcre"
       #"asio" -- XXX use package?
@@ -43,8 +43,8 @@ in stdenv.mkDerivation rec {
   name = "mongodb-${version}";
 
   src = fetchurl {
-    url = "http://downloads.mongodb.org/src/mongodb-src-r${version}.tar.gz";
-    sha256 = "06q6j2bjy31pjwqws53wdpmn2x8w2hafzsnv1s3wx15pc9vq3y15";
+    url = "https://fastdl.mongodb.org/src/mongodb-src-r${version}.tar.gz";
+    sha256 = "0n8vspccrpd2z9xk3yjpz4gprd730dfacw914ksjzz9iadn0zdi9";
   };
 
   nativeBuildInputs = [ scons ];
@@ -52,12 +52,6 @@ in stdenv.mkDerivation rec {
 
   patches =
     [
-      # When not building with the system valgrind, the build should use the
-      # vendored header file - regardless of whether or not we're using the system
-      # tcmalloc - so we need to lift the include path manipulation out of the
-      # conditional.
-      ./valgrind-include.patch
-
       # MongoDB keeps track of its build parameters, which tricks nix into
       # keeping dependencies to build inputs in the final output.
       # We remove the build flags from buildInfo data.
@@ -87,6 +81,8 @@ in stdenv.mkDerivation rec {
       --replace 'engine("wiredTiger")' 'engine("mmapv1")'
   '';
 
+  NIX_CFLAGS_COMPILE = stdenv.lib.optional stdenv.cc.isClang "-Wno-unused-command-line-argument";
+
   buildPhase = ''
     scons -j $NIX_BUILD_CORES core --release ${other-args}
   '';
diff --git a/pkgs/servers/nosql/mongodb/valgrind-include.patch b/pkgs/servers/nosql/mongodb/valgrind-include.patch
deleted file mode 100644
index 6b401525c080..000000000000
--- a/pkgs/servers/nosql/mongodb/valgrind-include.patch
+++ /dev/null
@@ -1,25 +0,0 @@
-diff --git a/src/mongo/util/SConscript b/src/mongo/util/SConscript
-index 6add602..6e232d8 100644
---- a/src/mongo/util/SConscript
-+++ b/src/mongo/util/SConscript
-@@ -241,9 +241,6 @@ if get_option('allocator') == 'tcmalloc':
-         # Add in the include path for our vendored tcmalloc.
-         tcmspEnv.InjectThirdPartyIncludePaths('gperftools')
- 
--        # Include valgrind since tcmalloc disables itself while running under valgrind
--        tcmspEnv.InjectThirdPartyIncludePaths('valgrind')
--
-         # If our changes to tcmalloc are ever upstreamed, this should become set based on a top
-         # level configure check, though its effects should still be scoped just to these files.
-         tcmspEnv.Append(
-@@ -252,6 +249,10 @@ if get_option('allocator') == 'tcmalloc':
-             ]
-         )
- 
-+    # Include valgrind since tcmalloc disables itself while running under valgrind
-+    if not use_system_version_of_library('valgrind'):
-+        tcmspEnv.InjectThirdPartyIncludePaths('valgrind')
-+
-     tcmspEnv.Library(
-         target='tcmalloc_set_parameter',
-         source=[