diff --git a/src/mongo/s/d_state.cpp b/src/mongo/s/d_state.cpp
index 4570886648a..eb3dca62040 100644
--- a/src/mongo/s/d_state.cpp
+++ b/src/mongo/s/d_state.cpp
@@ -82,16 +82,9 @@ namespace mongo {
           _configServerTickets( 3 /* max number of concurrent config server refresh threads */ ) {
     }
 
-    void ShardingState::enable( const string& server ) {
+    bool ShardingState::enabled() {
         boost::lock_guard<boost::mutex> lk(_mutex);
-
-        _enabled = true;
-        verify( server.size() );
-        if ( _configServer.size() == 0 )
-            _configServer = server;
-        else {
-            verify( server == _configServer );
-        }
+        return _enabled;
     }
 
     void ShardingState::initialize(const string& server) {
@@ -99,14 +92,7 @@ namespace mongo {
                 "Unable to obtain host name during sharding initialization.",
                 !getHostName().empty());
 
-        ShardedConnectionInfo::addHook();
-        shardingState.enable(server);
-
-        vector<string> configdbs;
-        splitStringDelim(server, &configdbs, ',');
-
-        configServer.init(configdbs);
-        grid.initCatalogManager(configdbs);
+        shardingState._initialize(server);
     }
 
     // TODO: Consolidate and eliminate these various ways of setting / validating shard names
@@ -191,7 +177,7 @@ namespace mongo {
         return true;
     }
 
-    const ChunkVersion ShardingState::getVersion( const string& ns ) const {
+    ChunkVersion ShardingState::getVersion(const string& ns) {
         boost::lock_guard<boost::mutex> lk(_mutex);
 
         CollectionMetadataMap::const_iterator it = _collMetadata.find( ns );
@@ -470,6 +456,28 @@ namespace mongo {
         return doRefreshMetadata(txn, ns, ChunkVersion(0, 0, OID()), false, latestShardVersion);
     }
 
+    void ShardingState::_initialize(const string& server) {
+        // Ensure only one caller at a time initializes
+        boost::lock_guard<boost::mutex> lk(_mutex);
+
+        if (_enabled) {
+            return;
+        }
+
+        ShardedConnectionInfo::addHook();
+
+        invariant(_configServer.empty());
+        _configServer = server;
+
+        vector<string> configdbs;
+        splitStringDelim(server, &configdbs, ',');
+
+        configServer.init(configdbs);
+        grid.initCatalogManager(configdbs);
+
+        _enabled = true;
+    }
+
     Status ShardingState::doRefreshMetadata( OperationContext* txn,
                                              const string& ns,
                                              const ChunkVersion& reqShardVersion,
diff --git a/src/mongo/s/d_state.h b/src/mongo/s/d_state.h
index 34368b0c143..3f528789a7f 100644
--- a/src/mongo/s/d_state.h
+++ b/src/mongo/s/d_state.h
@@ -49,9 +49,8 @@ namespace mongo {
     public:
         ShardingState();
 
-        bool enabled() const { return _enabled; }
+        bool enabled();
         const std::string& getConfigServer() const { return _configServer; }
-        void enable( const std::string& server );
 
         // Initialize sharding state and begin authenticating outgoing connections and handling
         // shard versions.  If this is not run before sharded operations occur auth will not work
@@ -75,7 +74,7 @@ namespace mongo {
 
         bool hasVersion( const std::string& ns );
         bool hasVersion( const std::string& ns , ChunkVersion& version );
-        const ChunkVersion getVersion( const std::string& ns ) const;
+        ChunkVersion getVersion(const std::string& ns);
 
         /**
          * If the metadata for 'ns' at this shard is at or above the requested version,
@@ -265,6 +264,8 @@ namespace mongo {
 
     private:
 
+        void _initialize(const std::string& server);
+
         /**
          * Refreshes collection metadata by asking the config server for the latest information.
          * May or may not be based on a requested version.
@@ -275,14 +276,16 @@ namespace mongo {
                                   bool useRequestedVersion,
                                   ChunkVersion* latestShardVersion );
 
-        bool _enabled;
-
         std::string _configServer;
 
         std::string _shardName;
 
         // protects state below
-        mutable mongo::mutex _mutex;
+        mongo::mutex _mutex;
+
+        // Whether ::initialize has been called
+        bool _enabled;
+
         // protects accessing the config server
         // Using a ticket holder so we can have multiple redundant tries at any given time
         mutable TicketHolder _configServerTickets;