merge default into bug24725

17 files changed, 493 insertions, 245 deletions

diff --git a/Makefile b/Makefile
index e8975856..d16cd4d0 100644
--- a/Makefile
+++ b/Makefile
@@ -216,12 +216,12 @@ start-rabbit-on-node: all
 stop-rabbit-on-node: all
 	echo "rabbit:stop()." | $(ERL_CALL)
 
-set-memory-alarm: all
-	echo "alarm_handler:set_alarm({{vm_memory_high_watermark, node()}, []})." | \
+set-resource-alarm: all
+	echo "alarm_handler:set_alarm({{resource_limit, $(SOURCE), node()}, []})." | \
 	$(ERL_CALL)
 
-clear-memory-alarm: all
-	echo "alarm_handler:clear_alarm({vm_memory_high_watermark, node()})." | \
+clear-resource-alarm: all
+	echo "alarm_handler:clear_alarm({resource_limit, $(SOURCE), node()})." | \
 	$(ERL_CALL)
 
 stop-node:
diff --git a/docs/rabbitmqctl.1.xml b/docs/rabbitmqctl.1.xml
index ee07ebfe..ded3ab48 100644
--- a/docs/rabbitmqctl.1.xml
+++ b/docs/rabbitmqctl.1.xml
@@ -948,7 +948,7 @@
                 <term>source_kind</term>
                 <listitem><para>The kind of the source of messages to
                 which the binding is attached. Currently always
-                queue. With non-ASCII characters escaped as in
+                exchange. With non-ASCII characters escaped as in
                 C.</para></listitem>
               </varlistentry>
               <varlistentry>
@@ -1074,8 +1074,8 @@
               <varlistentry>
                 <term>last_blocked_by</term>
                 <listitem><para>The reason for which this connection
-                    was last blocked. One of 'mem' - due to a memory
-                    alarm, 'flow' - due to internal flow control, or
+                    was last blocked. One of 'resource' - due to a memory
+                    or disk alarm, 'flow' - due to internal flow control, or
                     'none' if the connection was never
                     blocked.</para></listitem>
               </varlistentry>
diff --git a/ebin/rabbit_app.in b/ebin/rabbit_app.in
index fd19051d..b7d14f20 100644
--- a/ebin/rabbit_app.in
+++ b/ebin/rabbit_app.in
@@ -19,6 +19,7 @@
          {ssl_listeners, []},
          {ssl_options, []},
          {vm_memory_high_watermark, 0.4},
+         {disk_free_limit, {mem_relative, 1.0}},
          {msg_store_index_module, rabbit_msg_store_ets_index},
          {backing_queue_module, rabbit_variable_queue},
          {frame_max, 131072},
diff --git a/packaging/debs/Debian/debian/control b/packaging/debs/Debian/debian/control
index fb02cd6a..e935acf5 100644
--- a/packaging/debs/Debian/debian/control
+++ b/packaging/debs/Debian/debian/control
@@ -2,6 +2,8 @@ Source: rabbitmq-server
 Section: net
 Priority: extra
 Maintainer: RabbitMQ Team <packaging@rabbitmq.com>
+Uploader: Emile Joubert <emile@rabbitmq.com>
+DM-Upload-Allowed: yes
 Build-Depends: cdbs, debhelper (>= 5), erlang-dev, python-simplejson, xmlto, xsltproc, erlang-nox (>= 1:12.b.3), erlang-src (>= 1:12.b.3), unzip, zip
 Standards-Version: 3.8.0
 
diff --git a/src/dtree.erl b/src/dtree.erl
new file mode 100644
index 00000000..265bb340
--- /dev/null
+++ b/src/dtree.erl
@@ -0,0 +1,111 @@
+%% The contents of this file are subject to the Mozilla Public License
+%% Version 1.1 (the "License"); you may not use this file except in
+%% compliance with the License. You may obtain a copy of the License
+%% at http://www.mozilla.org/MPL/
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and
+%% limitations under the License.
+%%
+%% The Original Code is RabbitMQ.
+%%
+%% The Initial Developer of the Original Code is VMware, Inc.
+%% Copyright (c) 2007-2012 VMware, Inc.  All rights reserved.
+%%
+
+%% A dual-index tree.
+%%
+%% Conceptually, what we want is a map that has two distinct sets of
+%% keys (referred to here as primary and secondary, although that
+%% shouldn't imply a hierarchy) pointing to one set of
+%% values. However, in practice what we'll always want to do is insert
+%% a value that's pointed at by (one primary, many secondaries) and
+%% remove values that are pointed at by (one secondary, many
+%% primaries) or (one secondary, all primaries). Thus the API.
+%%
+%% Entries exists while they have a non-empty secondary key set. The
+%% 'take' operations return the entries that got removed, i.e. that
+%% had no remaining secondary keys. take/3 expects entries to exist
+%% with the supplied primary keys and secondary key. take/2 can cope
+%% with the supplied secondary key having no entries.
+
+-module(dtree).
+
+-export([empty/0, insert/4, take/3, take/2,
+         is_defined/2, is_empty/1, smallest/1, size/1]).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-export_type([?MODULE/0]).
+
+-opaque(?MODULE()  :: {gb_tree(), gb_tree()}).
+
+-type(pk()         :: any()).
+-type(sk()         :: any()).
+-type(val()        :: any()).
+-type(kv()         :: {pk(), val()}).
+
+-spec(empty/0      :: () -> ?MODULE()).
+-spec(insert/4     :: (pk(), [sk()], val(), ?MODULE()) -> ?MODULE()).
+-spec(take/3       :: ([pk()], sk(), ?MODULE()) -> {[kv()], ?MODULE()}).
+-spec(take/2       :: (sk(), ?MODULE()) -> {[kv()], ?MODULE()}).
+-spec(is_defined/2 :: (sk(), ?MODULE()) -> boolean()).
+-spec(is_empty/1   :: (?MODULE()) -> boolean()).
+-spec(smallest/1   :: (?MODULE()) -> kv()).
+-spec(size/1       :: (?MODULE()) -> non_neg_integer()).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+
+empty() -> {gb_trees:empty(), gb_trees:empty()}.
+
+insert(PK, SKs, V, {P, S}) ->
+    {gb_trees:insert(PK, {gb_sets:from_list(SKs), V}, P),
+     lists:foldl(fun (SK, S0) ->
+                         case gb_trees:lookup(SK, S0) of
+                             {value, PKS} -> PKS1 = gb_sets:insert(PK, PKS),
+                                             gb_trees:update(SK, PKS1, S0);
+                             none         -> PKS = gb_sets:singleton(PK),
+                                             gb_trees:insert(SK, PKS, S0)
+                         end
+                 end, S, SKs)}.
+
+take(PKs, SK, {P, S}) ->
+    {KVs, P1} = take2(PKs, SK, P),
+    PKS = gb_sets:difference(gb_trees:get(SK, S), gb_sets:from_list(PKs)),
+    {KVs, {P1, case gb_sets:is_empty(PKS) of
+                   true  -> gb_trees:delete(SK, S);
+                   false -> gb_trees:update(SK, PKS, S)
+               end}}.
+
+take(SK, {P, S}) ->
+    case gb_trees:lookup(SK, S) of
+        none         -> {[], {P, S}};
+        {value, PKS} -> {KVs, P1} = take2(gb_sets:to_list(PKS), SK, P),
+                        {KVs, {P1, gb_trees:delete(SK, S)}}
+    end.
+
+is_defined(SK, {_P, S}) -> gb_trees:is_defined(SK, S).
+
+is_empty({P, _S}) -> gb_trees:is_empty(P).
+
+smallest({P, _S}) -> {K, {_SKS, V}} = gb_trees:smallest(P),
+                     {K, V}.
+
+size({P, _S}) -> gb_trees:size(P).
+
+%%----------------------------------------------------------------------------
+
+take2(PKs, SK, P) ->
+    lists:foldl(fun (PK, {KVs, P0}) ->
+                        {SKS, V} = gb_trees:get(PK, P0),
+                        SKS1 = gb_sets:delete(SK, SKS),
+                        case gb_sets:is_empty(SKS1) of
+                            true  -> {[{PK, V} | KVs], gb_trees:delete(PK, P0)};
+                            false -> {KVs, gb_trees:update(PK, {SKS1, V}, P0)}
+                        end
+                end, {[], P}, PKs).
diff --git a/src/rabbit.erl b/src/rabbit.erl
index dd5fb89c..eec7e34e 100644
--- a/src/rabbit.erl
+++ b/src/rabbit.erl
@@ -327,7 +327,11 @@ status() ->
            [{vm_memory_high_watermark, {vm_memory_monitor,
                                         get_vm_memory_high_watermark, []}},
             {vm_memory_limit,          {vm_memory_monitor,
-                                        get_memory_limit, []}}]),
+                                        get_memory_limit, []}},
+            {disk_free_limit,          {rabbit_disk_monitor,
+                                        get_disk_free_limit, []}},
+            {disk_free,                {rabbit_disk_monitor,
+                                        get_disk_free, []}}]),
     S3 = rabbit_misc:with_exit_handler(
            fun () -> [] end,
            fun () -> [{file_descriptors, file_handle_cache:info()}] end),
diff --git a/src/rabbit_alarm.erl b/src/rabbit_alarm.erl
index 187ec1ab..04e0c141 100644
--- a/src/rabbit_alarm.erl
+++ b/src/rabbit_alarm.erl
@@ -23,7 +23,7 @@
 -export([init/1, handle_call/2, handle_event/2, handle_info/2,
          terminate/2, code_change/3]).
 
--export([remote_conserve_memory/2]). %% Internal use only
+-export([remote_conserve_resources/3]). %% Internal use only
 
 -record(alarms, {alertees, alarmed_nodes}).
 
@@ -45,6 +45,9 @@ start() ->
     ok = alarm_handler:add_alarm_handler(?MODULE, []),
     {ok, MemoryWatermark} = application:get_env(vm_memory_high_watermark),
     rabbit_sup:start_restartable_child(vm_memory_monitor, [MemoryWatermark]),
+
+    {ok, DiskLimit} = application:get_env(disk_free_limit),
+    rabbit_sup:start_restartable_child(rabbit_disk_monitor, [DiskLimit]),
     ok.
 
 stop() ->
@@ -61,41 +64,41 @@ on_node_down(Node) -> gen_event:notify(alarm_handler, {node_down, Node}).
 
 %% Can't use alarm_handler:{set,clear}_alarm because that doesn't
 %% permit notifying a remote node.
-remote_conserve_memory(Pid, true) ->
+remote_conserve_resources(Pid, Source, true) ->
     gen_event:notify({alarm_handler, node(Pid)},
-                     {set_alarm, {{vm_memory_high_watermark, node()}, []}});
-remote_conserve_memory(Pid, false) ->
+                     {set_alarm, {{resource_limit, Source, node()}, []}});
+remote_conserve_resources(Pid, Source, false) ->
     gen_event:notify({alarm_handler, node(Pid)},
-                     {clear_alarm, {vm_memory_high_watermark, node()}}).
+                     {clear_alarm, {resource_limit, Source, node()}}).
 
 %%----------------------------------------------------------------------------
 
 init([]) ->
     {ok, #alarms{alertees      = dict:new(),
-                 alarmed_nodes = sets:new()}}.
+                 alarmed_nodes = dict:new()}}.
 
 handle_call({register, Pid, HighMemMFA}, State) ->
-    {ok, 0 < sets:size(State#alarms.alarmed_nodes),
+    {ok, 0 < dict:size(State#alarms.alarmed_nodes),
      internal_register(Pid, HighMemMFA, State)};
 
 handle_call(_Request, State) ->
     {ok, not_understood, State}.
 
-handle_event({set_alarm, {{vm_memory_high_watermark, Node}, []}}, State) ->
-    {ok, maybe_alert(fun sets:add_element/2, Node, State)};
+handle_event({set_alarm, {{resource_limit, Source, Node}, []}}, State) ->
+    {ok, maybe_alert(fun dict:append/3, Node, Source, State)};
 
-handle_event({clear_alarm, {vm_memory_high_watermark, Node}}, State) ->
-    {ok, maybe_alert(fun sets:del_element/2, Node, State)};
+handle_event({clear_alarm, {resource_limit, Source, Node}}, State) ->
+    {ok, maybe_alert(fun dict_unappend/3, Node, Source, State)};
 
 handle_event({node_up, Node}, State) ->
     %% Must do this via notify and not call to avoid possible deadlock.
     ok = gen_event:notify(
            {alarm_handler, Node},
-           {register, self(), {?MODULE, remote_conserve_memory, []}}),
+           {register, self(), {?MODULE, remote_conserve_resources, []}}),
     {ok, State};
 
 handle_event({node_down, Node}, State) ->
-    {ok, maybe_alert(fun sets:del_element/2, Node, State)};
+    {ok, maybe_alert(fun dict_unappend_all/3, Node, [], State)};
 
 handle_event({register, Pid, HighMemMFA}, State) ->
     {ok, internal_register(Pid, HighMemMFA, State)};
@@ -118,34 +121,58 @@ code_change(_OldVsn, State, _Extra) ->
 
 %%----------------------------------------------------------------------------
 
-maybe_alert(SetFun, Node, State = #alarms{alarmed_nodes = AN,
-                                          alertees      = Alertees}) ->
-    AN1 = SetFun(Node, AN),
-    BeforeSz = sets:size(AN),
-    AfterSz  = sets:size(AN1),
+dict_unappend_all(Key, _Val, Dict) ->
+    dict:erase(Key, Dict).
+
+dict_unappend(Key, Val, Dict) ->
+    case lists:delete(Val, dict:fetch(Key, Dict)) of
+        [] -> dict:erase(Key, Dict);
+        X  -> dict:store(Key, X, Dict)
+    end.
+
+count_dict_values(Val, Dict) ->
+    dict:fold(fun (_Node, List, Count) ->
+                  Count + case lists:member(Val, List) of
+                              true  -> 1;
+                              false -> 0
+                          end
+              end, 0, Dict).
+
+maybe_alert(UpdateFun, Node, Source,
+            State = #alarms{alarmed_nodes = AN,
+                            alertees      = Alertees}) ->
+    AN1 = UpdateFun(Node, Source, AN),
+    BeforeSz = count_dict_values(Source, AN),
+    AfterSz  = count_dict_values(Source, AN1),
+
     %% If we have changed our alarm state, inform the remotes.
     IsLocal = Node =:= node(),
-    if IsLocal andalso BeforeSz < AfterSz -> ok = alert_remote(true,  Alertees);
-       IsLocal andalso BeforeSz > AfterSz -> ok = alert_remote(false, Alertees);
-       true                               -> ok
+    if IsLocal andalso BeforeSz < AfterSz ->
+           ok = alert_remote(true,  Alertees, Source);
+       IsLocal andalso BeforeSz > AfterSz ->
+           ok = alert_remote(false, Alertees, Source);
+       true                               ->
+           ok
     end,
     %% If the overall alarm state has changed, inform the locals.
-    case {BeforeSz, AfterSz} of
-        {0, 1} -> ok = alert_local(true,  Alertees);
-        {1, 0} -> ok = alert_local(false, Alertees);
+    case {dict:size(AN), dict:size(AN1)} of
+        {0, 1} -> ok = alert_local(true,  Alertees, Source);
+        {1, 0} -> ok = alert_local(false, Alertees, Source);
         {_, _} -> ok
     end,
     State#alarms{alarmed_nodes = AN1}.
 
-alert_local(Alert, Alertees)  -> alert(Alert, Alertees, fun erlang:'=:='/2).
+alert_local(Alert, Alertees, _Source) ->
+    alert(Alertees, [Alert], fun erlang:'=:='/2).
 
-alert_remote(Alert, Alertees) -> alert(Alert, Alertees, fun erlang:'=/='/2).
+alert_remote(Alert, Alertees, Source) ->
+    alert(Alertees, [Source, Alert], fun erlang:'=/='/2).
 
-alert(Alert, Alertees, NodeComparator) ->
+alert(Alertees, AlertArg, NodeComparator) ->
     Node = node(),
     dict:fold(fun (Pid, {M, F, A}, ok) ->
                       case NodeComparator(Node, node(Pid)) of
-                          true  -> apply(M, F, A ++ [Pid, Alert]);
+                          true  -> apply(M, F, A ++ [Pid] ++ AlertArg);
                           false -> ok
                       end
               end, ok, Alertees).
@@ -153,9 +180,9 @@ alert(Alert, Alertees, NodeComparator) ->
 internal_register(Pid, {M, F, A} = HighMemMFA,
                   State = #alarms{alertees = Alertees}) ->
     _MRef = erlang:monitor(process, Pid),
-    case sets:is_element(node(), State#alarms.alarmed_nodes) of
-        true  -> ok = apply(M, F, A ++ [Pid, true]);
-        false -> ok
+    case dict:find(node(), State#alarms.alarmed_nodes) of
+        {ok, _Sources} -> apply(M, F, A ++ [Pid, true]);
+        error          -> ok
     end,
     NewAlertees = dict:store(Pid, HighMemMFA, Alertees),
     State#alarms{alertees = NewAlertees}.
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index d643cecd..2de020bb 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -48,8 +48,7 @@
             ttl,
             ttl_timer_ref,
             publish_seqno,
-            unconfirmed_mq,
-            unconfirmed_qm,
+            unconfirmed,
             delayed_stop,
             queue_monitors,
             dlx,
@@ -135,8 +134,7 @@ init(Q) ->
                dlx                 = undefined,
                dlx_routing_key     = undefined,
                publish_seqno       = 1,
-               unconfirmed_mq      = gb_trees:empty(),
-               unconfirmed_qm      = gb_trees:empty(),
+               unconfirmed         = dtree:empty(),
                delayed_stop        = undefined,
                queue_monitors      = dict:new(),
                msg_id_to_channel   = gb_trees:empty()},
@@ -161,8 +159,7 @@ init_with_backing_queue_state(Q = #amqqueue{exclusive_owner = Owner}, BQ, BQS,
                expiry_timer_ref    = undefined,
                ttl                 = undefined,
                publish_seqno       = 1,
-               unconfirmed_mq      = gb_trees:empty(),
-               unconfirmed_qm      = gb_trees:empty(),
+               unconfirmed         = dtree:empty(),
                delayed_stop        = undefined,
                queue_monitors      = dict:new(),
                msg_id_to_channel   = MTC},
@@ -731,11 +728,9 @@ dead_letter_msg(Msg, AckTag, Reason, State = #q{dlx = DLX}) ->
     end.
 
 dead_letter_msg_existing_dlx(Msg, AckTag, Reason,
-                             State = #q{publish_seqno       = MsgSeqNo,
-                                        unconfirmed_mq      = UMQ,
-                                        dlx                 = DLX,
-                                        backing_queue       = BQ,
-                                        backing_queue_state = BQS}) ->
+                             State = #q{publish_seqno = MsgSeqNo,
+                                        unconfirmed   = UC,
+                                        dlx           = DLX}) ->
     {ok, _, QPids} =
         rabbit_basic:publish(
           rabbit_basic:delivery(
@@ -744,20 +739,9 @@ dead_letter_msg_existing_dlx(Msg, AckTag, Reason,
     State1 = lists:foldl(fun monitor_queue/2, State, QPids),
     State2 = State1#q{publish_seqno = MsgSeqNo + 1},
     case QPids of
-        [] -> {_Guids, BQS1} = BQ:ack([AckTag], BQS),
-              cleanup_after_confirm(State2#q{backing_queue_state = BQS1});
-        _  -> State3 =
-                  lists:foldl(
-                    fun(QPid, State0 = #q{unconfirmed_qm = UQM}) ->
-                            UQM1 = rabbit_misc:gb_trees_set_insert(
-                                     QPid, MsgSeqNo, UQM),
-                            State0#q{unconfirmed_qm = UQM1}
-                    end, State2, QPids),
-              noreply(State3#q{
-                        unconfirmed_mq =
-                            gb_trees:insert(
-                              MsgSeqNo, {gb_sets:from_list(QPids),
-                                         AckTag}, UMQ)})
+        [] -> cleanup_after_confirm([AckTag], State2);
+        _  -> UC1 = dtree:insert(MsgSeqNo, QPids, AckTag, UC),
+              noreply(State2#q{unconfirmed = UC1})
     end.
 
 monitor_queue(QPid, State = #q{queue_monitors = QMons}) ->
@@ -776,64 +760,31 @@ demonitor_queue(QPid, State = #q{queue_monitors = QMons}) ->
     end.
 
 handle_queue_down(QPid, Reason, State = #q{queue_monitors = QMons,
-                                           unconfirmed_qm = UQM}) ->
+                                           unconfirmed    = UC}) ->
     case dict:find(QPid, QMons) of
         error ->
             noreply(State);
         {ok, _} ->
             rabbit_log:info("DLQ ~p (for ~s) died~n",
                             [QPid, rabbit_misc:rs(qname(State))]),
-            State1 = State#q{queue_monitors = dict:erase(QPid, QMons)},
-            case gb_trees:lookup(QPid, UQM) of
-                none ->
-                    noreply(State1);
-                {value, MsgSeqNosSet} ->
-                    case rabbit_misc:is_abnormal_termination(Reason) of
-                        true  -> rabbit_log:warning(
-                                   "Dead queue lost ~p messages~n",
-                                   [gb_sets:size(MsgSeqNosSet)]);
-                        false -> ok
-                    end,
-                    handle_confirm(gb_sets:to_list(MsgSeqNosSet), QPid, State1)
-            end
+            {MsgSeqNoAckTags, UC1} = dtree:take(QPid, UC),
+            case (MsgSeqNoAckTags =/= [] andalso
+                  rabbit_misc:is_abnormal_termination(Reason)) of
+                true -> rabbit_log:warning("Dead queue lost ~p messages~n",
+                                           [length(MsgSeqNoAckTags)]);
+                false -> ok
+            end,
+            cleanup_after_confirm(
+              [AckTag || {_MsgSeqNo, AckTag} <- MsgSeqNoAckTags],
+              State#q{queue_monitors = dict:erase(QPid, QMons),
+                      unconfirmed    = UC1})
     end.
 
-handle_confirm(MsgSeqNos, QPid, State = #q{unconfirmed_mq      = UMQ,
-                                           unconfirmed_qm      = UQM,
-                                           backing_queue       = BQ,
-                                           backing_queue_state = BQS}) ->
-    {AckTags1, UMQ3} =
-        lists:foldl(
-          fun (MsgSeqNo, {AckTags, UMQ1}) ->
-                  {QPids, AckTag} = gb_trees:get(MsgSeqNo, UMQ1),
-                  QPids1 = gb_sets:delete(QPid, QPids),
-                  case gb_sets:is_empty(QPids1) of
-                      true  -> {[AckTag | AckTags],
-                                gb_trees:delete(MsgSeqNo, UMQ1)};
-                      false -> {AckTags, gb_trees:update(
-                                           MsgSeqNo, {QPids1, AckTag}, UMQ1)}
-                  end
-          end, {[], UMQ}, MsgSeqNos),
-    {_Guids, BQS1} = BQ:ack(AckTags1, BQS),
-    MsgSeqNos1 = gb_sets:difference(gb_trees:get(QPid, UQM),
-                                    gb_sets:from_list(MsgSeqNos)),
-    State1 = case gb_sets:is_empty(MsgSeqNos1) of
-                 false -> State#q{
-                            unconfirmed_qm =
-                                gb_trees:update(QPid, MsgSeqNos1, UQM)};
-                 true  -> demonitor_queue(
-                            QPid, State#q{
-                                    unconfirmed_qm =
-                                        gb_trees:delete(QPid, UQM)})
-             end,
-    cleanup_after_confirm(State1#q{unconfirmed_mq      = UMQ3,
-                                   backing_queue_state = BQS1}).
-
 stop_later(Reason, State) ->
     stop_later(Reason, undefined, noreply, State).
 
-stop_later(Reason, From, Reply, State = #q{unconfirmed_mq = UMQ}) ->
-    case {gb_trees:is_empty(UMQ), Reply} of
+stop_later(Reason, From, Reply, State = #q{unconfirmed = UC}) ->
+    case {dtree:is_empty(UC), Reply} of
         {true, noreply} ->
             {stop, Reason, State};
         {true, _} ->
@@ -842,16 +793,20 @@ stop_later(Reason, From, Reply, State = #q{unconfirmed_mq = UMQ}) ->
             noreply(State#q{delayed_stop = {Reason, {From, Reply}}})
     end.
 
-cleanup_after_confirm(State = #q{delayed_stop   = DS,
-                                 unconfirmed_mq = UMQ}) ->
-    case gb_trees:is_empty(UMQ) andalso DS =/= undefined of
+cleanup_after_confirm(AckTags, State = #q{delayed_stop        = DS,
+                                          unconfirmed         = UC,
+                                          backing_queue       = BQ,
+                                          backing_queue_state = BQS}) ->
+    {_Guids, BQS1} = BQ:ack(AckTags, BQS),
+    State1 = State#q{backing_queue_state = BQS1},
+    case dtree:is_empty(UC) andalso DS =/= undefined of
         true  -> case DS of
                      {_, {_, noreply}}  -> ok;
                      {_, {From, Reply}} -> gen_server2:reply(From, Reply)
                  end,
                  {Reason, _} = DS,
-                 {stop, Reason, State};
-        false -> noreply(State)
+                 {stop, Reason, State1};
+        false -> noreply(State1)
     end.
 
 already_been_here(_Delivery, #q{dlx = undefined}) ->
@@ -1232,8 +1187,14 @@ handle_call(force_event_refresh, _From,
     end,
     reply(ok, State).
 
-handle_cast({confirm, MsgSeqNos, QPid}, State) ->
-    handle_confirm(MsgSeqNos, QPid, State);
+handle_cast({confirm, MsgSeqNos, QPid}, State = #q{unconfirmed = UC}) ->
+    {MsgSeqNoAckTags, UC1} = dtree:take(MsgSeqNos, QPid, UC),
+    State1 = case dtree:is_defined(QPid, UC1) of
+                 false -> demonitor_queue(QPid, State);
+                 true  -> State
+             end,
+    cleanup_after_confirm([AckTag || {_MsgSeqNo, AckTag} <- MsgSeqNoAckTags],
+                          State1#q{unconfirmed = UC1});
 
 handle_cast(_, State = #q{delayed_stop = DS}) when DS =/= undefined ->
     noreply(State);
diff --git a/src/rabbit_basic.erl b/src/rabbit_basic.erl
index 25485ca0..a89aa074 100644
--- a/src/rabbit_basic.erl
+++ b/src/rabbit_basic.erl
@@ -199,9 +199,9 @@ replace_headers(Headers, Content = #content{properties = Props}) ->
 
 indexof(L, Element) -> indexof(L, Element, 1).
 
-indexof([], _Element, _N)              -> 0;
-indexof([Element | _Rest], Element, N) -> N;
-indexof([_ | Rest], Element, N)        -> indexof(Rest, Element, N + 1).
+indexof([],               _Element, _N) -> 0;
+indexof([Element | _Rest], Element,  N) -> N;
+indexof([_ | Rest],        Element,  N) -> indexof(Rest, Element, N + 1).
 
 is_message_persistent(#content{properties = #'P_basic'{
                                  delivery_mode = Mode}}) ->
diff --git a/src/rabbit_channel.erl b/src/rabbit_channel.erl
index cac622f8..4a0e93be 100644
--- a/src/rabbit_channel.erl
+++ b/src/rabbit_channel.erl
@@ -37,8 +37,8 @@
              uncommitted_message_q, uncommitted_acks, uncommitted_nacks, user,
              virtual_host, most_recently_declared_queue, queue_monitors,
              consumer_mapping, blocking, queue_consumers, queue_collector_pid,
-             stats_timer, confirm_enabled, publish_seqno, unconfirmed_mq,
-             unconfirmed_qm, confirmed, capabilities, trace_state}).
+             stats_timer, confirm_enabled, publish_seqno, unconfirmed,
+             confirmed, capabilities, trace_state}).
 
 -define(MAX_PERMISSION_CACHE_SIZE, 12).
 
@@ -201,8 +201,7 @@ init([Channel, ReaderPid, WriterPid, ConnPid, ConnName, Protocol, User, VHost,
                 queue_collector_pid     = CollectorPid,
                 confirm_enabled         = false,
                 publish_seqno           = 1,
-                unconfirmed_mq          = gb_trees:empty(),
-                unconfirmed_qm          = gb_trees:empty(),
+                unconfirmed             = dtree:empty(),
                 confirmed               = [],
                 capabilities            = Capabilities,
                 trace_state             = rabbit_trace:init(VHost)},
@@ -548,45 +547,9 @@ record_confirms(MXs, State = #ch{confirmed = C}) ->
 
 confirm([], _QPid, State) ->
     State;
-confirm(MsgSeqNos, QPid, State) ->
-    {MXs, State1} = process_confirms(MsgSeqNos, QPid, false, State),
-    record_confirms(MXs, State1).
-
-process_confirms(MsgSeqNos, QPid, Nack, State) ->
-    lists:foldl(
-      fun(MsgSeqNo, {_MXs, _State = #ch{unconfirmed_mq = UMQ0}} = Acc) ->
-              case gb_trees:lookup(MsgSeqNo, UMQ0) of
-                  {value, XQ} -> remove_unconfirmed(MsgSeqNo, QPid, XQ,
-                                                    Acc, Nack);
-                  none        -> Acc
-              end
-      end, {[], State}, MsgSeqNos).
-
-remove_unconfirmed(MsgSeqNo, QPid, {XName, Qs},
-                   {MXs, State = #ch{unconfirmed_mq = UMQ,
-                                     unconfirmed_qm = UQM}},
-                   Nack) ->
-    State1 = case gb_trees:lookup(QPid, UQM) of
-                 {value, MsgSeqNos} ->
-                     MsgSeqNos1 = gb_sets:delete(MsgSeqNo, MsgSeqNos),
-                     case gb_sets:is_empty(MsgSeqNos1) of
-                         true  -> UQM1 = gb_trees:delete(QPid, UQM),
-                                  State#ch{unconfirmed_qm = UQM1};
-                         false -> UQM1 = gb_trees:update(QPid, MsgSeqNos1, UQM),
-                                  State#ch{unconfirmed_qm = UQM1}
-                     end;
-                 none ->
-                     State
-             end,
-    Qs1 = gb_sets:del_element(QPid, Qs),
-    %% If QPid somehow died initiating a nack, clear the message from
-    %% internal data-structures.  Also, cleanup empty entries.
-    case (Nack orelse gb_sets:is_empty(Qs1)) of
-        true  -> UMQ1 = gb_trees:delete(MsgSeqNo, UMQ),
-                 {[{MsgSeqNo, XName} | MXs], State1#ch{unconfirmed_mq = UMQ1}};
-        false -> UMQ1 = gb_trees:update(MsgSeqNo, {XName, Qs1}, UMQ),
-                 {MXs, State1#ch{unconfirmed_mq = UMQ1}}
-    end.
+confirm(MsgSeqNos, QPid, State = #ch{unconfirmed = UC}) ->
+    {MXs, UC1} = dtree:take(MsgSeqNos, QPid, UC),
+    record_confirms(MXs, State#ch{unconfirmed = UC1}).
 
 handle_method(#'channel.open'{}, _, State = #ch{state = starting}) ->
     {reply, #'channel.open_ok'{}, State#ch{state = running}};
@@ -1152,22 +1115,12 @@ monitor_queue(QPid, State = #ch{queue_monitors = QMons}) ->
         true  -> State
     end.
 
-handle_publishing_queue_down(QPid, Reason, State = #ch{unconfirmed_qm = UQM}) ->
-    MsgSeqNos = case gb_trees:lookup(QPid, UQM) of
-                    {value, MsgSet} -> gb_sets:to_list(MsgSet);
-                    none            -> []
-                end,
-    %% We remove the MsgSeqNos from UQM before calling
-    %% process_confirms to prevent each MsgSeqNo being removed from
-    %% the set one by one which which would be inefficient
-    State1 = State#ch{unconfirmed_qm = gb_trees:delete_any(QPid, UQM)},
-    {Nack, SendFun} =
-        case rabbit_misc:is_abnormal_termination(Reason) of
-            true  -> {true,  fun send_nacks/2};
-            false -> {false, fun record_confirms/2}
-        end,
-    {MXs, State2} = process_confirms(MsgSeqNos, QPid, Nack, State1),
-    SendFun(MXs, State2).
+handle_publishing_queue_down(QPid, Reason, State = #ch{unconfirmed = UC}) ->
+    {MXs, UC1} = dtree:take(QPid, UC),
+    (case rabbit_misc:is_abnormal_termination(Reason) of
+         true  -> fun send_nacks/2;
+         false -> fun record_confirms/2
+     end)(MXs, State#ch{unconfirmed = UC1}).
 
 handle_consuming_queue_down(QPid,
                             State = #ch{consumer_mapping = ConsumerMapping,
@@ -1392,21 +1345,8 @@ process_routing_result(routed,       [], XName,  MsgSeqNo,   _, State) ->
 process_routing_result(routed,        _,     _, undefined,   _, State) ->
     State;
 process_routing_result(routed,    QPids, XName,  MsgSeqNo,   _, State) ->
-    #ch{unconfirmed_mq = UMQ} = State,
-    UMQ1 = gb_trees:insert(MsgSeqNo, {XName, gb_sets:from_list(QPids)}, UMQ),
-    SingletonSet = gb_sets:singleton(MsgSeqNo),
-    lists:foldl(
-      fun (QPid, State0 = #ch{unconfirmed_qm = UQM}) ->
-              case gb_trees:lookup(QPid, UQM) of
-                  {value, MsgSeqNos} ->
-                      MsgSeqNos1 = gb_sets:insert(MsgSeqNo, MsgSeqNos),
-                      UQM1 = gb_trees:update(QPid, MsgSeqNos1, UQM),
-                      State0#ch{unconfirmed_qm = UQM1};
-                  none ->
-                      UQM1 = gb_trees:insert(QPid, SingletonSet, UQM),
-                      State0#ch{unconfirmed_qm = UQM1}
-              end
-      end, State#ch{unconfirmed_mq = UMQ1}, QPids).
+    State#ch{unconfirmed = dtree:insert(MsgSeqNo, QPids, XName,
+                                        State#ch.unconfirmed)}.
 
 send_nacks([], State) ->
     State;
@@ -1444,11 +1384,11 @@ send_confirms(Cs, State) ->
                           end, State).
 
 coalesce_and_send(MsgSeqNos, MkMsgFun,
-                  State = #ch{writer_pid = WriterPid, unconfirmed_mq = UMQ}) ->
+                  State = #ch{writer_pid = WriterPid, unconfirmed = UC}) ->
     SMsgSeqNos = lists:usort(MsgSeqNos),
-    CutOff = case gb_trees:is_empty(UMQ) of
+    CutOff = case dtree:is_empty(UC) of
                  true  -> lists:last(SMsgSeqNos) + 1;
-                 false -> {SeqNo, _XQ} = gb_trees:smallest(UMQ), SeqNo
+                 false -> {SeqNo, _XName} = dtree:smallest(UC), SeqNo
              end,
     {Ms, Ss} = lists:splitwith(fun(X) -> X < CutOff end, SMsgSeqNos),
     case Ms of
@@ -1462,8 +1402,8 @@ coalesce_and_send(MsgSeqNos, MkMsgFun,
 
 maybe_complete_tx(State = #ch{tx_status = in_progress}) ->
     State;
-maybe_complete_tx(State = #ch{unconfirmed_mq = UMQ}) ->
-    case gb_trees:is_empty(UMQ) of
+maybe_complete_tx(State = #ch{unconfirmed = UC}) ->
+    case dtree:is_empty(UC) of
         false -> State;
         true  -> complete_tx(State#ch{confirmed = []})
     end.
@@ -1491,8 +1431,8 @@ i(confirm,        #ch{confirm_enabled  = CE})      -> CE;
 i(name,           State)                           -> name(State);
 i(consumer_count, #ch{consumer_mapping = ConsumerMapping}) ->
     dict:size(ConsumerMapping);
-i(messages_unconfirmed, #ch{unconfirmed_mq = UMQ}) ->
-    gb_trees:size(UMQ);
+i(messages_unconfirmed, #ch{unconfirmed = UC}) ->
+    dtree:size(UC);
 i(messages_unacknowledged, #ch{unacked_message_q = UAMQ}) ->
     queue:len(UAMQ);
 i(messages_uncommitted, #ch{uncommitted_message_q = TMQ}) ->
diff --git a/src/rabbit_control.erl b/src/rabbit_control.erl
index 6a775adf..51f88c8f 100644
--- a/src/rabbit_control.erl
+++ b/src/rabbit_control.erl
@@ -328,7 +328,7 @@ action(set_vm_memory_high_watermark, Node, [Arg], _Opts, Inform) ->
                              0 -> Arg ++ ".0";
                              _ -> Arg
                          end),
-    Inform("Setting memory threshhold on ~p to ~p", [Node, Frac]),
+    Inform("Setting memory threshold on ~p to ~p", [Node, Frac]),
     rpc_call(Node, vm_memory_monitor, set_vm_memory_high_watermark, [Frac]);
 
 action(set_permissions, Node, [Username, CPerm, WPerm, RPerm], Opts, Inform) ->
diff --git a/src/rabbit_disk_monitor.erl b/src/rabbit_disk_monitor.erl
new file mode 100644
index 00000000..831d5290
--- /dev/null
+++ b/src/rabbit_disk_monitor.erl
@@ -0,0 +1,196 @@
+%% The contents of this file are subject to the Mozilla Public License
+%% Version 1.1 (the "License"); you may not use this file except in
+%% compliance with the License. You may obtain a copy of the License
+%% at http://www.mozilla.org/MPL/
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and
+%% limitations under the License.
+%%
+%% The Original Code is RabbitMQ.
+%%
+%% The Initial Developer of the Original Code is VMware, Inc.
+%% Copyright (c) 2007-2012 VMware, Inc.  All rights reserved.
+%%
+
+-module(rabbit_disk_monitor).
+
+-behaviour(gen_server).
+
+-export([start_link/1]).
+
+-export([init/1, handle_call/3, handle_cast/2, handle_info/2,
+         terminate/2, code_change/3]).
+
+-export([get_disk_free_limit/0, set_disk_free_limit/1, get_check_interval/0,
+         set_check_interval/1, get_disk_free/0]).
+
+-define(SERVER, ?MODULE).
+-define(DEFAULT_DISK_CHECK_INTERVAL, 60000).
+
+-record(state, {dir,
+                limit,
+                timeout,
+                timer,
+                alarmed
+               }).
+
+%%----------------------------------------------------------------------------
+
+-ifdef(use_specs).
+
+-type(disk_free_limit() :: (integer() | {'mem_relative', float()})).
+-spec(start_link/1 :: (disk_free_limit()) -> rabbit_types:ok_pid_or_error()).
+-spec(get_disk_free_limit/0 :: () -> integer()).
+-spec(set_disk_free_limit/1 :: (disk_free_limit()) -> 'ok').
+-spec(get_check_interval/0 :: () -> integer()).
+-spec(set_check_interval/1 :: (integer()) -> 'ok').
+-spec(get_disk_free/0 :: () -> (integer() | 'unknown')).
+
+-endif.
+
+%%----------------------------------------------------------------------------
+%% Public API
+%%----------------------------------------------------------------------------
+
+get_disk_free_limit() ->
+    gen_server:call(?MODULE, get_disk_free_limit, infinity).
+
+set_disk_free_limit(Limit) ->
+    gen_server:call(?MODULE, {set_disk_free_limit, Limit}, infinity).
+
+get_check_interval() ->
+    gen_server:call(?MODULE, get_check_interval, infinity).
+
+set_check_interval(Interval) ->
+    gen_server:call(?MODULE, {set_check_interval, Interval}, infinity).
+
+get_disk_free() ->
+    gen_server:call(?MODULE, get_disk_free, infinity).
+
+%%----------------------------------------------------------------------------
+%% gen_server callbacks
+%%----------------------------------------------------------------------------
+
+start_link(Args) ->
+    gen_server:start_link({local, ?SERVER}, ?MODULE, [Args], []).
+
+init([Limit]) ->
+    TRef = start_timer(?DEFAULT_DISK_CHECK_INTERVAL),
+    Dir = dir(),
+    State = #state { dir     = Dir,
+                     timeout = ?DEFAULT_DISK_CHECK_INTERVAL,
+                     timer   = TRef,
+                     alarmed = false},
+    case {catch get_disk_free(Dir),
+          vm_memory_monitor:get_total_memory()} of
+        {N1, N2} when is_integer(N1), is_integer(N2) ->
+            {ok, set_disk_limits(State, Limit)};
+        _ ->
+            rabbit_log:info("Disabling disk free space monitoring "
+                            "on unsupported platform~n"),
+            {stop, unsupported_platform}
+    end.
+
+handle_call(get_disk_free_limit, _From, State) ->
+    {reply, interpret_limit(State#state.limit), State};
+
+handle_call({set_disk_free_limit, Limit}, _From, State) ->
+    {reply, ok, set_disk_limits(State, Limit)};
+
+handle_call(get_check_interval, _From, State) ->
+    {reply, State#state.timeout, State};
+
+handle_call({set_check_interval, Timeout}, _From, State) ->
+    {ok, cancel} = timer:cancel(State#state.timer),
+    {reply, ok, State#state{timeout = Timeout, timer = start_timer(Timeout)}};
+
+handle_call(get_disk_free, _From, State = #state { dir = Dir }) ->
+    {reply, get_disk_free(Dir), State};
+
+handle_call(_Request, _From, State) ->
+    {noreply, State}.
+
+handle_cast(_Request, State) ->
+    {noreply, State}.
+
+handle_info(update, State) ->
+    {noreply, internal_update(State)};
+
+handle_info(_Info, State) ->
+    {noreply, State}.
+
+terminate(_Reason, _State) ->
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+%%----------------------------------------------------------------------------
+%% Server Internals
+%%----------------------------------------------------------------------------
+
+% the partition / drive containing this directory will be monitored
+dir() -> rabbit_mnesia:dir().
+
+set_disk_limits(State, Limit) ->
+    State1 = State#state { limit = Limit },
+    rabbit_log:info("Disk free limit set to ~pMB~n",
+                    [trunc(interpret_limit(Limit) / 1048576)]),
+    internal_update(State1).
+
+internal_update(State = #state { limit   = Limit,
+                                 dir     = Dir,
+                                 alarmed = Alarmed}) ->
+    CurrentFreeBytes = get_disk_free(Dir),
+    LimitBytes = interpret_limit(Limit),
+    NewAlarmed = CurrentFreeBytes < LimitBytes,
+    case {Alarmed, NewAlarmed} of
+        {false, true} ->
+            emit_update_info("exceeded", CurrentFreeBytes, LimitBytes),
+            alarm_handler:set_alarm({{resource_limit, disk, node()}, []});
+        {true, false} ->
+            emit_update_info("below limit", CurrentFreeBytes, LimitBytes),
+            alarm_handler:clear_alarm({resource_limit, disk, node()});
+        _ ->
+            ok
+    end,
+    State #state {alarmed = NewAlarmed}.
+
+get_disk_free(Dir) ->
+    get_disk_free(Dir, os:type()).
+
+get_disk_free(Dir, {unix, Sun})
+  when Sun =:= sunos; Sun =:= sunos4; Sun =:= solaris ->
+    parse_free_unix(rabbit_misc:os_cmd("/usr/bin/df -k " ++ Dir));
+get_disk_free(Dir, {unix, _}) ->
+    parse_free_unix(rabbit_misc:os_cmd("/bin/df -kP " ++ Dir));
+get_disk_free(Dir, {win32, _}) ->
+    parse_free_win32(rabbit_misc:os_cmd("dir /-C /W " ++ Dir));
+get_disk_free(_, _) ->
+    unknown.
+
+parse_free_unix(CommandResult) ->
+    [_, Stats | _] = string:tokens(CommandResult, "\n"),
+    [_FS, _Total, _Used, Free | _] = string:tokens(Stats, " \t"),
+    list_to_integer(Free) * 1024.
+
+parse_free_win32(CommandResult) ->
+    LastLine = lists:last(string:tokens(CommandResult, "\r\n")),
+    [_, _Dir, Free, "bytes", "free"] = string:tokens(LastLine, " "),
+    list_to_integer(Free).
+
+interpret_limit({mem_relative, R}) ->
+    round(R * vm_memory_monitor:get_total_memory());
+interpret_limit(L) ->
+    L.
+
+emit_update_info(State, CurrentFree, Limit) ->
+    rabbit_log:info(
+      "Disk free space limit now ~s. Free bytes:~p Limit:~p~n",
+      [State, CurrentFree, Limit]).
+
+start_timer(Timeout) ->
+    {ok, TRef} = timer:send_interval(Timeout, update),
+    TRef.
diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index ddf7f574..c1be7613 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -46,8 +46,7 @@
 -export([sort_field_table/1]).
 -export([pid_to_string/1, string_to_pid/1]).
 -export([version_compare/2, version_compare/3]).
--export([dict_cons/3, orddict_cons/3, gb_trees_cons/3,
-         gb_trees_set_insert/3]).
+-export([dict_cons/3, orddict_cons/3, gb_trees_cons/3]).
 -export([gb_trees_fold/3, gb_trees_foreach/2]).
 -export([get_options/2]).
 -export([all_module_attributes/1, build_acyclic_graph/3]).
@@ -60,6 +59,7 @@
 -export([append_rpc_all_nodes/4]).
 -export([multi_call/2]).
 -export([quit/1]).
+-export([os_cmd/1]).
 
 %%----------------------------------------------------------------------------
 
@@ -176,7 +176,6 @@
 -spec(dict_cons/3 :: (any(), any(), dict()) -> dict()).
 -spec(orddict_cons/3 :: (any(), any(), orddict:orddict()) -> orddict:orddict()).
 -spec(gb_trees_cons/3 :: (any(), any(), gb_tree()) -> gb_tree()).
--spec(gb_trees_set_insert/3 :: (any(), any(), gb_tree()) -> gb_tree()).
 -spec(gb_trees_fold/3 :: (fun ((any(), any(), A) -> A), A, gb_tree()) -> A).
 -spec(gb_trees_foreach/2 ::
         (fun ((any(), any()) -> any()), gb_tree()) -> 'ok').
@@ -204,6 +203,7 @@
 -spec(multi_call/2 ::
         ([pid()], any()) -> {[{pid(), any()}], [{pid(), any()}]}).
 -spec(quit/1 :: (integer() | string()) -> no_return()).
+-spec(os_cmd/1 :: (string()) -> string()).
 
 -endif.
 
@@ -717,15 +717,6 @@ gb_trees_cons(Key, Value, Tree) ->
         none            -> gb_trees:insert(Key, [Value], Tree)
     end.
 
-gb_trees_set_insert(Key, Value, Tree) ->
-    case gb_trees:lookup(Key, Tree) of
-        {value, Values} ->
-            Values1 = gb_sets:insert(Value, Values),
-            gb_trees:update(Key, Values1, Tree);
-        none ->
-            gb_trees:insert(Key, gb_sets:singleton(Value), Tree)
-    end.
-
 gb_trees_fold(Fun, Acc, Tree) ->
     gb_trees_fold1(Fun, Acc, gb_trees:next(gb_trees:iterator(Tree))).
 
@@ -914,3 +905,10 @@ quit(Status) ->
         {unix,  _} -> halt(Status);
         {win32, _} -> init:stop(Status)
     end.
+
+os_cmd(Command) ->
+    Exec = hd(string:tokens(Command, " ")),
+    case os:find_executable(Exec) of
+        false -> throw({command_not_found, Exec});
+        _     -> os:cmd(Command)
+    end.
diff --git a/src/rabbit_reader.erl b/src/rabbit_reader.erl
index 47e796dc..5e9e78d3 100644
--- a/src/rabbit_reader.erl
+++ b/src/rabbit_reader.erl
@@ -25,7 +25,7 @@
 
 -export([init/4, mainloop/2]).
 
--export([conserve_memory/2, server_properties/1]).
+-export([conserve_resources/2, server_properties/1]).
 
 -define(HANDSHAKE_TIMEOUT, 10).
 -define(NORMAL_TIMEOUT, 3).
@@ -38,7 +38,7 @@
 -record(v1, {parent, sock, connection, callback, recv_len, pending_recv,
              connection_state, queue_collector, heartbeater, stats_timer,
              channel_sup_sup_pid, start_heartbeat_fun, buf, buf_len,
-             auth_mechanism, auth_state, conserve_memory,
+             auth_mechanism, auth_state, conserve_resources,
              last_blocked_by, last_blocked_at}).
 
 -define(STATISTICS_KEYS, [pid, recv_oct, recv_cnt, send_oct, send_cnt,
@@ -71,7 +71,7 @@
 -spec(info/2 :: (pid(), rabbit_types:info_keys()) -> rabbit_types:infos()).
 -spec(force_event_refresh/1 :: (pid()) -> 'ok').
 -spec(shutdown/2 :: (pid(), string()) -> 'ok').
--spec(conserve_memory/2 :: (pid(), boolean()) -> 'ok').
+-spec(conserve_resources/2 :: (pid(), boolean()) -> 'ok').
 -spec(server_properties/1 :: (rabbit_types:protocol()) ->
                                   rabbit_framing:amqp_table()).
 
@@ -133,8 +133,8 @@ info(Pid, Items) ->
 force_event_refresh(Pid) ->
     gen_server:cast(Pid, force_event_refresh).
 
-conserve_memory(Pid, Conserve) ->
-    Pid ! {conserve_memory, Conserve},
+conserve_resources(Pid, Conserve) ->
+    Pid ! {conserve_resources, Conserve},
     ok.
 
 server_properties(Protocol) ->
@@ -218,7 +218,7 @@ start_connection(Parent, ChannelSupSupPid, Collector, StartHeartbeatFun, Deb,
                 buf_len             = 0,
                 auth_mechanism      = none,
                 auth_state          = none,
-                conserve_memory     = false,
+                conserve_resources  = false,
                 last_blocked_by     = none,
                 last_blocked_at     = never},
     try
@@ -276,8 +276,8 @@ mainloop(Deb, State = #v1{sock = Sock, buf = Buf, buf_len = BufLen}) ->
         {other, Other}  -> handle_other(Other, Deb, State)
     end.
 
-handle_other({conserve_memory, Conserve}, Deb, State) ->
-    recvloop(Deb, control_throttle(State#v1{conserve_memory = Conserve}));
+handle_other({conserve_resources, Conserve}, Deb, State) ->
+    recvloop(Deb, control_throttle(State#v1{conserve_resources = Conserve}));
 handle_other({channel_closing, ChPid}, Deb, State) ->
     ok = rabbit_channel:ready_for_close(ChPid),
     channel_cleanup(ChPid),
@@ -358,8 +358,8 @@ terminate(Explanation, State) when ?IS_RUNNING(State) ->
 terminate(_Explanation, State) ->
     {force, State}.
 
-control_throttle(State = #v1{connection_state = CS,
-                             conserve_memory  = Mem}) ->
+control_throttle(State = #v1{connection_state   = CS,
+                             conserve_resources = Mem}) ->
     case {CS, Mem orelse credit_flow:blocked()} of
         {running,   true} -> State#v1{connection_state = blocking};
         {blocking, false} -> State#v1{connection_state = running};
@@ -377,9 +377,9 @@ maybe_block(State = #v1{connection_state = blocking}) ->
 maybe_block(State) ->
     State.
 
-update_last_blocked_by(State = #v1{conserve_memory = true}) ->
-    State#v1{last_blocked_by = mem};
-update_last_blocked_by(State = #v1{conserve_memory = false}) ->
+update_last_blocked_by(State = #v1{conserve_resources = true}) ->
+    State#v1{last_blocked_by = resource};
+update_last_blocked_by(State = #v1{conserve_resources = false}) ->
     State#v1{last_blocked_by = flow}.
 
 close_connection(State = #v1{queue_collector = Collector,
@@ -701,11 +701,11 @@ handle_method0(#'connection.open'{virtual_host = VHostPath},
     ok = rabbit_access_control:check_vhost_access(User, VHostPath),
     NewConnection = Connection#connection{vhost = VHostPath},
     ok = send_on_channel0(Sock, #'connection.open_ok'{}, Protocol),
-    Conserve = rabbit_alarm:register(self(), {?MODULE, conserve_memory, []}),
+    Conserve = rabbit_alarm:register(self(), {?MODULE, conserve_resources, []}),
     State1 = control_throttle(
-               State#v1{connection_state = running,
-                        connection       = NewConnection,
-                        conserve_memory  = Conserve}),
+               State#v1{connection_state   = running,
+                        connection         = NewConnection,
+                        conserve_resources = Conserve}),
     rabbit_event:notify(connection_created,
                         [{type, network} |
                          infos(?CREATION_EVENT_KEYS, State1)]),
diff --git a/src/rabbit_sup.erl b/src/rabbit_sup.erl
index 0965e3b3..bf2b4798 100644
--- a/src/rabbit_sup.erl
+++ b/src/rabbit_sup.erl
@@ -52,22 +52,20 @@ start_child(Mod, Args) ->
     start_child(Mod, Mod, Args).
 
 start_child(ChildId, Mod, Args) ->
-    {ok, _} = supervisor:start_child(?SERVER,
-                                     {ChildId, {Mod, start_link, Args},
-                                      transient, ?MAX_WAIT, worker, [Mod]}),
-    ok.
+    child_reply(supervisor:start_child(?SERVER,
+                                       {ChildId, {Mod, start_link, Args},
+                                        transient, ?MAX_WAIT, worker, [Mod]})).
 
 start_restartable_child(Mod) ->
     start_restartable_child(Mod, []).
 
 start_restartable_child(Mod, Args) ->
     Name = list_to_atom(atom_to_list(Mod) ++ "_sup"),
-    {ok, _} = supervisor:start_child(
-                ?SERVER,
-                {Name, {rabbit_restartable_sup, start_link,
-                        [Name, {Mod, start_link, Args}]},
-                 transient, infinity, supervisor, [rabbit_restartable_sup]}),
-    ok.
+    child_reply(supervisor:start_child(
+                  ?SERVER,
+                  {Name, {rabbit_restartable_sup, start_link,
+                          [Name, {Mod, start_link, Args}]},
+                   transient, infinity, supervisor, [rabbit_restartable_sup]})).
 
 stop_child(ChildId) ->
     case supervisor:terminate_child(?SERVER, ChildId) of
@@ -77,3 +75,9 @@ stop_child(ChildId) ->
 
 init([]) ->
     {ok, {{one_for_all, 0, 1}, []}}.
+
+
+%%----------------------------------------------------------------------------
+
+child_reply({ok, _}) -> ok;
+child_reply(X)       -> X.
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 55e4a6f8..e356d7ff 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -883,6 +883,8 @@ test_cluster_management() ->
                                         "invalid2@invalid"]),
     ok = assert_ram_node(),
 
+    ok = control_action(reset, []),
+
     SecondaryNode = rabbit_nodes:make("hare"),
     case net_adm:ping(SecondaryNode) of
         pong -> passed = test_cluster_management2(SecondaryNode);
@@ -898,7 +900,6 @@ test_cluster_management2(SecondaryNode) ->
     SecondaryNodeS = atom_to_list(SecondaryNode),
 
     %% make a disk node
-    ok = control_action(reset, []),
     ok = control_action(cluster, [NodeS]),
     ok = assert_disc_node(),
     %% make a ram node
@@ -1244,6 +1245,9 @@ test_confirms() ->
                                           },
                       rabbit_basic:build_content(
                         #'P_basic'{delivery_mode = 2}, <<"">>)),
+    %% We must not kill the queue before the channel has processed the
+    %% 'publish'.
+    ok = rabbit_channel:flush(Ch),
     %% Crash the queue
     QPid1 ! boom,
     %% Wait for a nack
diff --git a/src/vm_memory_monitor.erl b/src/vm_memory_monitor.erl
index fca55f02..fb184d1a 100644
--- a/src/vm_memory_monitor.erl
+++ b/src/vm_memory_monitor.erl
@@ -181,10 +181,10 @@ internal_update(State = #state { memory_limit = MemLimit,
     case {Alarmed, NewAlarmed} of
         {false, true} ->
             emit_update_info(set, MemUsed, MemLimit),
-            alarm_handler:set_alarm({{vm_memory_high_watermark, node()}, []});
+            alarm_handler:set_alarm({{resource_limit, memory, node()}, []});
         {true, false} ->
             emit_update_info(clear, MemUsed, MemLimit),
-            alarm_handler:clear_alarm({vm_memory_high_watermark, node()});
+            alarm_handler:clear_alarm({resource_limit, memory, node()});
         _ ->
             ok
     end,