diff --git a/lib/mongo/connection.rb b/lib/mongo/connection.rb
index 97a5dc7..b6f005c 100644
--- a/lib/mongo/connection.rb
+++ b/lib/mongo/connection.rb
@@ -30,6 +30,8 @@ module Mongo
     Mutex = ::Mutex
     ConditionVariable = ::ConditionVariable
 
+    Thread.abort_on_exception = true
+
     DEFAULT_PORT = 27017
     STANDARD_HEADER_SIZE = 16
     RESPONSE_HEADER_SIZE = 20
@@ -487,8 +489,10 @@ module Mongo
         end
 
         result = ''
-        send_message_on_socket(packed_message, sock)
-        result = receive(sock, request_id, exhaust)
+        @safe_mutexes[sock].synchronize do
+          send_message_on_socket(packed_message, sock)
+          result = receive(sock, request_id, exhaust)
+        end
       ensure
         if should_checkin
           checkin(sock)
@@ -628,6 +632,9 @@ module Mongo
       # Default maximum BSON object size
       @max_bson_size = Mongo::DEFAULT_MAX_BSON_SIZE
 
+      @safe_mutex_lock = Mutex.new
+      @safe_mutexes = Hash.new {|hash, key| hash[key] = Mutex.new}
+
       # Determine whether to use SSL.
       @ssl = opts.fetch(:ssl, false)
       if @ssl
diff --git a/lib/mongo/repl_set_connection.rb b/lib/mongo/repl_set_connection.rb
index 10617fe..3328bec 100644
--- a/lib/mongo/repl_set_connection.rb
+++ b/lib/mongo/repl_set_connection.rb
@@ -23,7 +23,7 @@ module Mongo
   # Instantiates and manages connections to a MongoDB replica set.
   class ReplSetConnection < Connection
     attr_reader :secondaries, :arbiters, :secondary_pools,
-      :replica_set_name, :read_pool, :seeds, :primary_tag_pool,
+      :replica_set_name, :read_pool, :seeds, :tag_map,
       :refresh_interval, :refresh_mode
 
     # Create a connection to a MongoDB replica set.
@@ -143,7 +143,7 @@ module Mongo
 
       # Maps
       @sockets_to_pools = {}
-      @primary_tag_pool = nil
+      @tag_map = nil
 
       # Replica set name
       if opts[:rs_name]
@@ -197,7 +197,10 @@ module Mongo
     #   to get the refresh lock.
     def refresh(opts={})
       if !connected?
-        @logger.warn("Not connected")
+        log(:info, "Trying to refresh but not connected..." +
+           "skipping replica set health check.")
+        hard_refresh!
+        return true
       end
 
       log(:info, "Checking replica set connection health...")
@@ -286,13 +289,6 @@ module Mongo
           @refresh_thread = nil
         end
 
-        if @nodes
-          @nodes.each do |member|
-            member.close
-          end
-        end
-
-        @nodes = []
         @read_pool = nil
 
         if @secondary_pools
@@ -304,7 +300,7 @@ module Mongo
         @secondaries      = []
         @secondary_pools  = []
         @arbiters         = []
-        @primary_tag_pool = nil
+        @tag_map = nil
         @sockets_to_pools.clear
       end
     end
@@ -359,7 +355,7 @@ module Mongo
       @primary_pool = manager.primary_pool
       @read_pool    = manager.read_pool
       @secondary_pools = manager.secondary_pools
-      @primary_tag_pool = manager.primary_tag_pool
+      @tag_map = manager.tag_map
       @seeds = manager.seeds
       @manager = manager
       @nodes = manager.nodes
@@ -407,7 +403,7 @@ module Mongo
     def checkout_tagged(tags)
       sync_synchronize(:SH) do
         tags.each do |k, v|
-          pool = @primary_tag_pool[{k.to_s => v}]
+          pool = @tag_map[{k.to_s => v}]
           if pool
             socket = pool.checkout
             @sockets_to_pools[socket] = pool
@@ -472,7 +468,11 @@ module Mongo
         if pool = @sockets_to_pools[socket]
           pool.checkin(socket)
         elsif socket
+          begin
           socket.close
+          rescue IOError
+            log(:info, "Tried to close socket #{socket} but already closed.")
+          end
         end
       end
 
diff --git a/lib/mongo/util/node.rb b/lib/mongo/util/node.rb
index de639b9..7407a67 100644
--- a/lib/mongo/util/node.rb
+++ b/lib/mongo/util/node.rb
@@ -14,6 +14,7 @@ module Mongo
       end
       @address = "#{host}:#{port}"
       @config = nil
+      @socket = nil
     end
 
     def eql?(other)
diff --git a/lib/mongo/util/pool_manager.rb b/lib/mongo/util/pool_manager.rb
index a273d1c..b1a87d1 100644
--- a/lib/mongo/util/pool_manager.rb
+++ b/lib/mongo/util/pool_manager.rb
@@ -3,12 +3,13 @@ module Mongo
 
     attr_reader :connection, :seeds, :arbiters, :primary, :secondaries,
       :primary_pool, :read_pool, :secondary_pools, :hosts, :nodes, :max_bson_size,
-      :tags_to_pools, :primary_tag_pool, :members
+      :tags_to_pools, :tag_map, :members
 
     def initialize(connection, seeds)
       @connection = connection
       @seeds = seeds
       @previously_connected = false
+      @refresh_required = false
     end
 
     def inspect
@@ -25,7 +26,7 @@ module Mongo
       initialize_pools(members)
       update_seed_list(members)
       set_read_pool
-      set_primary_tag_pools
+      set_tag_mappings
 
       @members = members
       @previously_connected = true
@@ -36,8 +37,6 @@ module Mongo
     # to our view. If any of these isn't the case,
     # set @refresh_require to true, and return.
     def check_connection_health
-      @refresh_required = false
-
       begin
         seed = get_valid_seed_node
       rescue ConnectionFailure
@@ -108,6 +107,8 @@ module Mongo
         elsif member.last_state == :secondary &&
           member.secondary?
           return true
+        else # This node isn't what it used to be.
+          return false
         end
       end
     end
@@ -122,7 +123,7 @@ module Mongo
       @hosts = Set.new
       @members = Set.new
       @tags_to_pools = {}
-      @primary_tag_pool = {}
+      @tag_map = {}
     end
 
     # Connect to each member of the replica set
@@ -195,12 +196,12 @@ module Mongo
 
     # If there's more than one pool associated with
     # a given tag, choose a close one using the bucket method.
-    def set_primary_tag_pools
+    def set_tag_mappings
       @tags_to_pools.each do |key, pool_list|
         if pool_list.length == 1
-          @primary_tag_pool[key] = pool_list.first
+          @tag_map[key] = pool_list.first
         else
-          @primary_tag_pool[key] = nearby_pool_from_set(pool_list)
+          @tag_map[key] = nearby_pool_from_set(pool_list)
         end
       end
     end
diff --git a/test/replica_sets/basic_test.rb b/test/replica_sets/basic_test.rb
index d79cf9c..c590350 100644
--- a/test/replica_sets/basic_test.rb
+++ b/test/replica_sets/basic_test.rb
@@ -40,7 +40,7 @@ class ConnectTest < Test::Unit::TestCase
     assert @conn.secondary_pools.include?(@conn.read_pool)
     assert_equal seeds.sort {|a,b| a[1] <=> b[1]},
       @conn.seeds.sort {|a,b| a[1] <=> b[1]}
-    assert_equal 5, @conn.tags_to_pools.keys.length
+    assert_equal 5, @conn.tag_map.keys.length
     assert_equal 90, @conn.refresh_interval
     assert_equal @conn.refresh_mode, :sync
   end
diff --git a/test/replica_sets/pooled_insert_test.rb b/test/replica_sets/pooled_insert_test.rb
deleted file mode 100644
index 90ed2cf..0000000
--- a/test/replica_sets/pooled_insert_test.rb
+++ /dev/null
@@ -1,58 +0,0 @@
-$:.unshift(File.join(File.dirname(__FILE__), '..', 'lib'))
-require './test/replica_sets/rs_test_helper'
-
-# NOTE: This test expects a replica set of three nodes to be running
-# on the local host.
-class ReplicaSetPooledInsertTest < Test::Unit::TestCase
-  include Mongo
-
-  def setup
-    @conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-      [RS.host, RS.ports[2]], :pool_size => 5, :timeout => 5)
-    @db = @conn.db(MONGO_TEST_DB)
-    @db.drop_collection("test-sets")
-    @coll = @db.collection("test-sets")
-  end
-
-  def teardown
-    RS.restart_killed_nodes
-    @conn.close if @conn
-  end
-
-  def test_insert
-    expected_results = [-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
-    @coll.save({:a => -1}, :safe => true)
-
-    RS.kill_primary
-
-    threads = []
-    10.times do |i|
-      threads[i] = Thread.new do
-        rescue_connection_failure do
-          @coll.save({:a => i}, :safe => true)
-        end
-      end
-    end
-
-    threads.each {|t| t.join}
-
-    # Restart the old master and wait for sync
-    RS.restart_killed_nodes
-    sleep(1)
-    results = []
-
-    rescue_connection_failure do
-      @coll.find.each {|r| results << r}
-      expected_results.each do |a|
-        assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a}"
-      end
-    end
-
-    @coll.save({:a => 10}, :safe => true)
-    @coll.find.each {|r| results << r}
-    (expected_results + [10]).each do |a|
-      assert results.any? {|r| r['a'] == a}, "Could not find record for a => #{a} on second find"
-    end
-  end
-
-end
diff --git a/test/replica_sets/refresh_test.rb b/test/replica_sets/refresh_test.rb
index ecad881..9d7174f 100644
--- a/test/replica_sets/refresh_test.rb
+++ b/test/replica_sets/refresh_test.rb
@@ -20,12 +20,12 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
       x.report("Connect") do
         10.times do
           ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-            [RS.host, RS.ports[2]], :background_refresh => false)
+            [RS.host, RS.ports[2]], :refresh_mode => false)
         end
       end
 
           @con = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-            [RS.host, RS.ports[2]], :background_refresh => false)
+            [RS.host, RS.ports[2]], :refresh_mode => false)
 
       x.report("manager") do
         man = Mongo::PoolManager.new(@con, @con.seeds)
@@ -41,7 +41,7 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
 
     rescue_connection_failure do
       @conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-        [RS.host, RS.ports[2]], :background_refresh => false)
+        [RS.host, RS.ports[2]], :refresh_mode => false)
     end
 
     assert_equal [], @conn.secondaries
@@ -70,7 +70,7 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
 
     rescue_connection_failure do
       @conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-        [RS.host, RS.ports[2]], :refresh_interval => 2, :background_refresh => true)
+        [RS.host, RS.ports[2]], :refresh_interval => 2, :refresh_mode => :sync)
     end
 
     assert_equal [], @conn.secondaries
@@ -87,8 +87,9 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
 
   def test_automated_refresh_with_removed_node
     @conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-      [RS.host, RS.ports[2]], :refresh_interval => 2, :background_refresh => true)
+      [RS.host, RS.ports[2]], :refresh_interval => 2, :refresh_mode => :sync)
 
+    p @conn.secondary_pools
     assert_equal 2, @conn.secondary_pools.length
     assert_equal 2, @conn.secondaries.length
 
@@ -103,13 +104,13 @@ class ReplicaSetRefreshTest < Test::Unit::TestCase
 
   def test_adding_and_removing_nodes
     @conn = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-      [RS.host, RS.ports[2]], :refresh_interval => 2, :background_refresh => true)
+      [RS.host, RS.ports[2]], :refresh_interval => 2, :refresh_mode => :async)
 
     RS.add_node
     sleep(5)
 
     @conn2 = ReplSetConnection.new([RS.host, RS.ports[0]], [RS.host, RS.ports[1]],
-      [RS.host, RS.ports[2]], :refresh_interval => 2, :background_refresh => true)
+      [RS.host, RS.ports[2]], :refresh_interval => 2, :refresh_mode => :async)
 
     assert @conn2.secondaries == @conn.secondaries
     assert_equal 3, @conn.secondary_pools.length
diff --git a/test/tools/repl_set_manager.rb b/test/tools/repl_set_manager.rb
index 2978ead..b916599 100644
--- a/test/tools/repl_set_manager.rb
+++ b/test/tools/repl_set_manager.rb
@@ -46,6 +46,7 @@ class ReplSetManager
     begin
     con = Mongo::Connection.new(@host, @start_port)
       rescue Mongo::ConnectionFailure
+      con = false
     end
 
     if con && ensure_up(1, con)
@@ -187,10 +188,7 @@ class ReplSetManager
   def kill(node, signal=2)
     pid = @mongods[node]['pid']
     puts "** Killing node with pid #{pid} at port #{@mongods[node]['port']}"
-    begin
-      get_connection(node)['admin'].command({'shutdown' => 1})
-    rescue Mongo::ConnectionFailure
-    end
+    system("kill -2 #{pid}")
     @mongods[node]['up'] = false
   end
 
@@ -300,10 +298,11 @@ class ReplSetManager
   private
 
   def initiate
+    puts "Initiating replica set..."
     con = get_connection
 
     attempt do
-      con['admin'].command({'replSetInitiate' => @config})
+      p con['admin'].command({'replSetInitiate' => @config})
     end
 
     con.close