diff --git a/.gitignore b/.gitignore
index fc482c42..96b65b68 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 node_modules
 config/environments/*.js
 .idea
+tools/munin/windshaft.conf
diff --git a/Makefile b/Makefile
index 424a3c91..c6eee208 100644
--- a/Makefile
+++ b/Makefile
@@ -7,9 +7,19 @@ clean:
 config/environments/test.js: config/environments/test.js.example
 	./configure
 
-check: config/environments/test.js
+check-local: config/environments/test.js
 	./run_tests.sh ${RUNTESTFLAGS} \
     test/unit/cartodb/redis_pool.test.js \
     test/unit/cartodb/req2params.test.js \
     test/acceptance/cache_validator.js \
     test/acceptance/server.js
+
+check-submodules:
+	for sub in windshaft grainstore mapnik; do \
+		test -e node_modules/$${sub} && make -C node_modules/$${sub} check; \
+	done
+
+check-full: check-local check-submodules
+
+check: check-local
+
diff --git a/NEWS.md b/NEWS.md
index 3cef2d0a..57db4db3 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,6 +1,25 @@
+1.1.8
+-----
+* Require Windshaft-0.9.1, to reduce harmfulness of cache_buster param
+
+1.1.7 (DD//MM//YY)
+-----
+* Do not let /etc/services confuse FD checker (munin plugin)
+* Multilayer support (#72)
+* Expose renderer settings in the environment config files
+
+1.1.6 (19//02//13)
+-----
+* Require windshaft 0.8.5, fixing some stability issues
+  and providing cache info on request
+* Require grainstore 0.10.9, fixing an issue with multi-geom markers
+* Enhance run_tests.sh to allow running single tests and skipping preparation
+* Fix async throws in getGeometryType, getInfoWindow and getMapMetadata
+* Survive connection refusals from redis
+* Add maxConnection environment configuration, default to 128
+
 1.1.5 (DD//MM//YY)
 -----
-* Enhance run_tests.sh to allow running single tests and skipping preparation
 * Fix bogus cached return of utf grid for fully contained tiles (#67)
 
 1.1.4 (DD//MM//YY)
diff --git a/app.js b/app.js
index f432a617..845a3cd6 100755
--- a/app.js
+++ b/app.js
@@ -10,9 +10,9 @@
 
 // sanity check
 var ENV = process.argv[2]
-if (ENV != 'development' && ENV != 'production'){
+if (ENV != 'development' && ENV != 'production' && ENV != 'staging' ){
     console.error("\nnode app.js [environment]");
-    console.error("environments: [development, production]\n");
+    console.error("environments: [development, production, staging]\n");
     process.exit(1);
 }
 
@@ -33,7 +33,19 @@ var Windshaft = require('windshaft');
 var serverOptions = require('./lib/cartodb/server_options');
 
 ws = CartodbWindshaft(serverOptions);
+
+// Maximum number of connections for one process
+// 128 is a good number if you have up to 1024 filedescriptors
+// 4 is good if you have max 32 filedescriptors
+// 1 is good if you have max 16 filedescriptors
+ws.maxConnections = global.environment.maxConnections || 128;
+
 ws.listen(global.environment.port, global.environment.host);
+
 ws.on('listening', function() {
   console.log("Windshaft tileserver started on " + global.environment.host + ':' + global.environment.port);
 });
+
+process.on('SIGUSR1', function() {
+  ws.dumpCacheStats();
+});
diff --git a/cluster.js b/cluster.js
index d5501d17..84ac8040 100755
--- a/cluster.js
+++ b/cluster.js
@@ -36,6 +36,9 @@ var serverOptions = require('./lib/cartodb/server_options');
 
 var ws = CartodbWindshaft(serverOptions);
 
+// Maximum number of connections for one process (see apps.js)
+ws.maxConnections = global.environment.maxConnections || 128;
+
 //.use(cluster.logger('logs'))
 //.use(cluster.stats())
 //.use(cluster.pidfiles('pids'))
@@ -48,9 +51,14 @@ var cluster = new Cluster({
   noWorkers: 1 
 });
 
+console.log(new Date().toISOString() + " - " + process.pid + " - Windshaft cluster starting");
+
 cluster.listen(function(cb) {
   cb(ws);
 }, function() {
   console.log("Windshaft tileserver started on port " + global.environment.port);
 });
 
+process.on('SIGUSR1', function() {
+  ws.dumpCacheStats();
+});
diff --git a/config/environments/development.js.example b/config/environments/development.js.example
index 050cfc45..9c8c10f8 100644
--- a/config/environments/development.js.example
+++ b/config/environments/development.js.example
@@ -2,11 +2,14 @@ var config = {
      environment: 'development'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds 
     ,socket_timeout: 600000
     ,enable_cors: true
     ,cache_enabled: false
-    ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
+    ,log_format: '[:date] :req[X-Real-IP] :method :req[Host]:url :status :response-time ms -> :res[Content-Type]'
     ,postgres_auth_user: 'development_cartodb_user_<%= user_id %>'
     ,postgres: {
         // Parameters to pass to datasource plugin of mapnik
@@ -26,14 +29,28 @@ var config = {
         max_size: 500
     }
     ,mapnik_version: undefined
+    ,renderer: {
+      // Milliseconds since last access before renderer cache item expires
+      cache_ttl: 60000,
+      metatile: 4,
+      bufferSize: 64
+    }
     ,millstone: {
         cache_basedir: '/tmp/cdb-tiler-dev/millstone-dev'
     }
     ,redis: {
         host: '127.0.0.1',
         port: 6379,
-        idleTimeoutMillis: 1,
-        reapIntervalMillis: 1
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 1, // idle time before dropping connection
+        reapIntervalMillis: 1 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'http',
diff --git a/config/environments/production.js.example b/config/environments/production.js.example
index e7a76715..5ee29407 100644
--- a/config/environments/production.js.example
+++ b/config/environments/production.js.example
@@ -2,11 +2,14 @@ var config = {
     environment: 'production'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true
     ,cache_enabled: true
-    ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
+    ,log_format: '[:date] :req[X-Real-IP] :method :req[Host]:url :status :response-time ms -> :res[Content-Type]'
     ,postgres_auth_user: 'cartodb_user_<%= user_id %>'
     ,postgres: {
         // Parameters to pass to datasource plugin of mapnik
@@ -20,12 +23,28 @@ var config = {
         max_size: 500
     }
     ,mapnik_version: undefined
+    ,renderer: {
+      // Milliseconds since last access before renderer cache item expires
+      cache_ttl: 60000,
+      metatile: 4,
+      bufferSize: 64
+    }
     ,millstone: {
         cache_basedir: '/home/ubuntu/tile_assets/'
     }
     ,redis: {
         host: '127.0.0.1',
-        port: 6379
+        port: 6379,
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 30000, // idle time before dropping connection
+        reapIntervalMillis: 1000 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'https',
diff --git a/config/environments/staging.js.example b/config/environments/staging.js.example
index dedb5001..7fc660c5 100644
--- a/config/environments/staging.js.example
+++ b/config/environments/staging.js.example
@@ -2,11 +2,14 @@ var config = {
     environment: 'production'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true
     ,cache_enabled: true
-    ,log_format: '[:date] :req[X-Real-IP] \033[90m:method\033[0m \033[36m:req[Host]:url\033[0m \033[90m:status :response-time ms -> :res[Content-Type]\033[0m'
+    ,log_format: '[:date] :req[X-Real-IP] :method :req[Host]:url :status :response-time ms -> :res[Content-Type]'
     ,postgres_auth_user: 'cartodb_staging_user_<%= user_id %>'
     ,postgres: {
         // Parameters to pass to datasource plugin of mapnik
@@ -20,12 +23,28 @@ var config = {
         max_size: 500
     }
     ,mapnik_version: undefined
+    ,renderer: {
+      // Milliseconds since last access before renderer cache item expires
+      cache_ttl: 60000,
+      metatile: 4,
+      bufferSize: 64
+    }
     ,millstone: {
         cache_basedir: '/home/ubuntu/tile_assets/'
     }
     ,redis: {
         host: '127.0.0.1',
-        port: 6379
+        port: 6379,
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 30000, // idle time before dropping connection
+        reapIntervalMillis: 1000 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'https',
diff --git a/config/environments/test.js.example b/config/environments/test.js.example
index 096acb03..b97b9a6d 100644
--- a/config/environments/test.js.example
+++ b/config/environments/test.js.example
@@ -2,6 +2,9 @@ var config = {
      environment: 'test'
     ,port: 8888
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true
@@ -20,14 +23,28 @@ var config = {
         max_size: 500
     }
     ,mapnik_version: '2.0.2'
+    ,renderer: {
+      // Milliseconds since last access before renderer cache item expires
+      cache_ttl: 60000,
+      metatile: 4,
+      bufferSize: 64
+    }
     ,millstone: {
         cache_basedir: '/tmp/cdb-tiler-test/millstone'
     }
     ,redis: {
         host: '127.0.0.1',
         port: 6333,
-        idleTimeoutMillis: 1,
-        reapIntervalMillis: 1
+        // Max number of connections in each pool.
+        // Users will be put on a queue when the limit is hit.
+        // Set to maxConnection to have no possible queues.
+        // There are currently 3 pools involved in serving
+        // windshaft-cartodb requests so multiply this number
+        // by 3 to know how many possible connections will be
+        // kept open by the server. The default is 50.
+        max: 50,
+        idleTimeoutMillis: 1, // idle time before dropping connection
+        reapIntervalMillis: 1 // time between cleanups
     }
     ,sqlapi: {
         protocol: 'http',
diff --git a/lib/cartodb/carto_data.js b/lib/cartodb/carto_data.js
index 5ad4723c..e43b7233 100644
--- a/lib/cartodb/carto_data.js
+++ b/lib/cartodb/carto_data.js
@@ -106,7 +106,7 @@ module.exports = function() {
                 if (check_result === 1) {
                     // authorized by key, login as db owner 
                     that.getId(req, function(err, user_id) {
-                        if (err) throw new Error(err);
+                        if (err) throw err;
                         var dbuser = _.template(global.settings.postgres_auth_user, {user_id: user_id});
                         _.extend(req, {dbuser:dbuser});
                         callback(err, true); 
@@ -126,7 +126,6 @@ module.exports = function() {
                 that.retrieve(that.table_metadata_db, redisKey, 'privacy', this);
             },
             function(err, data){
-                //if (err) throw err;
                 callback(err, data);
              }
         );
@@ -152,7 +151,6 @@ module.exports = function() {
                 that.retrieve(that.table_metadata_db, redisKey, 'the_geom_type', this);
             },
             function(err, data){
-                if (err) throw err;
                 callback(err, data);
             }
         );
@@ -172,7 +170,6 @@ module.exports = function() {
                 that.retrieve(that.table_metadata_db, redisKey, 'infowindow', this);
             },
             function(err, data){
-                if (err) throw err;
                 callback(err, data);
             }
         );
@@ -193,7 +190,6 @@ module.exports = function() {
                 that.retrieve(that.table_metadata_db, redisKey, 'map_metadata', this);
             },
             function(err, data){
-                if (err) throw err;
                 callback(err, data);
             }
         );
@@ -227,13 +223,13 @@ module.exports = function() {
                 redis_pool.acquire(db, this);
             },
             function executeQuery(err, data) {
+                if ( err ) throw err;
                 redisClient = data;
                 redisArgs.push(this);
                 redisClient[redisFunc.toUpperCase()].apply(redisClient, redisArgs);
             },
             function releaseRedisClient(err, data) {
-                if (err) throw err;
-                redis_pool.release(db, redisClient);
+                if ( ! _.isUndefined(redisClient) ) redis_pool.release(db, redisClient);
                 callback(err, data);
             }
         );
diff --git a/lib/cartodb/redis_pool.js b/lib/cartodb/redis_pool.js
index ea5c1bd5..d2c40cc2 100644
--- a/lib/cartodb/redis_pool.js
+++ b/lib/cartodb/redis_pool.js
@@ -58,8 +58,11 @@ var RedisPool = function(opts){
           client.send_anyway = true;
           client.select(database);  
           client.send_anyway = false;
+          callback(null, client);
         });    
-        return callback(null, client);
+        client.on('error', function (err) {
+          callback(err, null);
+        });
       },
       destroy: function(client) { 
         return client.quit(); 
diff --git a/lib/cartodb/server_options.js b/lib/cartodb/server_options.js
index 79141a2c..ac9c458f 100644
--- a/lib/cartodb/server_options.js
+++ b/lib/cartodb/server_options.js
@@ -6,13 +6,28 @@ var   _          = require('underscore')
   ;
 
 module.exports = function(){
+
+    var rendererConfig = _.defaults(global.environment.renderer || {}, {
+      cache_ttl: 60000,
+      metatile: 4,
+      bufferSize: 64
+    });
+
     var me = {
         base_url: '/tiles/:table',
+        base_url_notable: '/tiles',
         grainstore: {
           datasource: global.environment.postgres,
           cachedir: global.environment.millstone.cache_basedir,
           mapnik_version: global.environment.mapnik_version || mapnik.versions.mapnik
         },
+        mapnik: {
+          metatile: rendererConfig.metatile,
+          bufferSize: rendererConfig.bufferSize
+        },
+        renderCache: {
+          ttl: rendererConfig.cache_ttl
+        },
         redis: global.environment.redis,
         enable_cors: global.environment.enable_cors,
         varnish_host: global.environment.varnish.host,
diff --git a/npm-shrinkwrap.json b/npm-shrinkwrap.json
index 8c631486..3ef03a44 100644
--- a/npm-shrinkwrap.json
+++ b/npm-shrinkwrap.json
@@ -1,6 +1,6 @@
 {
   "name": "windshaft-cartodb",
-  "version": "1.1.5",
+  "version": "1.1.7",
   "dependencies": {
     "cluster2": {
       "version": "0.3.5-cdb02",
@@ -13,7 +13,7 @@
               "version": "1.9.2",
               "dependencies": {
                 "formidable": {
-                  "version": "1.0.11"
+                  "version": "1.0.12"
                 }
               }
             },
@@ -32,22 +32,22 @@
           "version": "0.8.3"
         },
         "npm": {
-          "version": "1.1.69",
+          "version": "1.2.12",
           "dependencies": {
             "semver": {
-              "version": "1.1.1"
+              "version": "1.1.3"
             },
             "ini": {
-              "version": "1.0.5"
+              "version": "1.1.0"
             },
             "slide": {
               "version": "1.1.3"
             },
             "abbrev": {
-              "version": "1.0.3"
+              "version": "1.0.4"
             },
             "graceful-fs": {
-              "version": "1.1.14"
+              "version": "1.2.0"
             },
             "minimatch": {
               "version": "0.2.9",
@@ -58,10 +58,10 @@
               }
             },
             "nopt": {
-              "version": "2.0.0"
+              "version": "2.1.1"
             },
             "rimraf": {
-              "version": "2.0.2"
+              "version": "2.1.4"
             },
             "request": {
               "version": "2.9.203",
@@ -71,10 +71,10 @@
               "version": "1.0.5"
             },
             "tar": {
-              "version": "0.1.14"
+              "version": "0.1.16"
             },
             "fstream": {
-              "version": "0.1.19"
+              "version": "0.1.22"
             },
             "block-stream": {
               "version": "0.0.6"
@@ -98,13 +98,13 @@
               "version": "2.0.4"
             },
             "node-gyp": {
-              "version": "0.7.3"
+              "version": "0.8.4"
             },
             "fstream-npm": {
               "version": "0.1.3",
               "dependencies": {
                 "fstream-ignore": {
-                  "version": "0.0.5"
+                  "version": "0.0.6"
                 }
               }
             },
@@ -124,7 +124,7 @@
               "version": "0.1.2"
             },
             "npm-registry-client": {
-              "version": "0.2.10",
+              "version": "0.2.17",
               "dependencies": {
                 "couch-login": {
                   "version": "0.1.15"
@@ -132,13 +132,13 @@
               }
             },
             "read-package-json": {
-              "version": "0.1.11"
+              "version": "0.2.0"
             },
             "read-installed": {
-              "version": "0.0.3"
+              "version": "0.1.1"
             },
             "glob": {
-              "version": "3.1.14"
+              "version": "3.1.20"
             },
             "init-package-json": {
               "version": "0.0.6",
@@ -152,7 +152,7 @@
               "version": "0.0.3"
             },
             "lockfile": {
-              "version": "0.2.1"
+              "version": "0.3.0"
             },
             "retry": {
               "version": "0.6.0"
@@ -161,10 +161,10 @@
               "version": "1.1.1"
             },
             "npmconf": {
-              "version": "0.0.16",
+              "version": "0.0.23",
               "dependencies": {
                 "config-chain": {
-                  "version": "1.1.3",
+                  "version": "1.1.5",
                   "dependencies": {
                     "proto-list": {
                       "version": "1.2.2"
@@ -187,28 +187,31 @@
       "version": "1.3.3"
     },
     "grainstore": {
-      "version": "0.10.8",
+      "version": "0.11.1",
       "dependencies": {
         "carto": {
           "version": "0.9.3-cdb2",
           "from": "git://github.com/CartoDB/carto.git#cdb-0.9",
           "dependencies": {
+            "mapnik-reference": {
+              "version": "5.0.0-cdb1",
+              "from": "git://github.com/CartoDB/mapnik-reference.git#cdb-5.0"
+            },
             "xml2js": {
               "version": "0.1.14",
               "dependencies": {
                 "sax": {
-                  "version": "0.4.2"
+                  "version": "0.5.2"
                 }
               }
             }
           }
         },
         "mapnik-reference": {
-          "version": "5.0.0-cdb1",
-          "from": "git://github.com/CartoDB/mapnik-reference.git#cdb-5.0"
+          "version": "5.0.4"
         },
         "millstone": {
-          "version": "0.5.13",
+          "version": "0.5.15",
           "dependencies": {
             "request": {
               "version": "2.11.4",
@@ -235,26 +238,26 @@
               }
             },
             "srs": {
-              "version": "0.2.18"
+              "version": "0.2.20"
             },
             "zipfile": {
-              "version": "0.3.3"
+              "version": "0.3.4"
             },
             "sqlite3": {
               "version": "2.1.5"
             },
             "mime": {
-              "version": "1.2.7"
+              "version": "1.2.9"
             },
             "mkdirp": {
-              "version": "0.3.4"
+              "version": "0.3.5"
             }
           }
         }
       }
     },
     "windshaft": {
-      "version": "0.8.2",
+      "version": "0.9.1",
       "dependencies": {
         "express": {
           "version": "2.5.11",
@@ -263,7 +266,7 @@
               "version": "1.9.2",
               "dependencies": {
                 "formidable": {
-                  "version": "1.0.11"
+                  "version": "1.0.12"
                 }
               }
             },
@@ -324,10 +327,10 @@
       "version": "2.9.202"
     },
     "mapnik": {
-      "version": "0.7.18"
+      "version": "0.7.22"
     },
     "semver": {
-      "version": "1.1.1"
+      "version": "1.1.3"
     },
     "mocha": {
       "version": "1.2.1",
@@ -350,7 +353,7 @@
           "version": "1.0.2"
         },
         "debug": {
-          "version": "0.7.0"
+          "version": "0.7.2"
         }
       }
     }
diff --git a/package.json b/package.json
index 85e3afe1..fab65f18 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
     "private": true,
     "name": "windshaft-cartodb",
-    "version": "1.1.5",
+    "version": "1.1.8",
     "description": "A map tile server for CartoDB",
     "url": "https://github.com/Vizzuality/Windshaft-cartodb",
     "licenses": [{
@@ -21,10 +21,10 @@
         "cluster2": "git://github.com/CartoDB/cluster2.git#cdb_production",
         "node-varnish": "0.1.1",
         "underscore"  : "~1.3.3",
-        "grainstore"  : "~0.10.8",
-        "windshaft"  : "~0.8.2",
+        "grainstore"  : "~0.11.1",
+        "windshaft"  : "~0.9.1",
         "step": "0.0.x",
-        "generic-pool": "1.0.x",
+        "generic-pool": "~1.0.12",
         "redis": "0.7.2",
         "hiredis": "~0.1.14",
         "request": "2.9.202",
diff --git a/test/acceptance/multilayer.js b/test/acceptance/multilayer.js
new file mode 100644
index 00000000..91e37b34
--- /dev/null
+++ b/test/acceptance/multilayer.js
@@ -0,0 +1,148 @@
+var assert      = require('../support/assert');
+var tests       = module.exports = {};
+var _           = require('underscore');
+var redis       = require('redis');
+var querystring = require('querystring');
+var semver      = require('semver');
+var mapnik      = require('mapnik');
+var Step        = require('step');
+
+require(__dirname + '/../support/test_helper');
+
+var windshaft_fixtures = __dirname + '/../../node_modules/windshaft/test/fixtures';
+
+var CartodbWindshaft = require(__dirname + '/../../lib/cartodb/cartodb_windshaft');
+var serverOptions = require(__dirname + '/../../lib/cartodb/server_options');
+var server = new CartodbWindshaft(serverOptions);
+server.setMaxListeners(0);
+
+suite('multilayer', function() {
+
+    var redis_client = redis.createClient(global.environment.redis.port);
+
+    suiteSetup(function(){
+    });
+
+    test("layergroup with 2 layers, each with its style", function(done) {
+
+      var layergroup =  {
+        version: '1.0.0',
+        layers: [
+           { options: {
+               sql: 'select cartodb_id, ST_Translate(the_geom_webmercator, 5e6, 0) as the_geom_webmercator from test_table limit 2',
+               cartocss: '#layer { marker-fill:red; marker-width:32; marker-allow-overlap:true; }', 
+               cartocss_version: '2.0.1' 
+             } },
+           { options: {
+               sql: 'select cartodb_id, ST_Translate(the_geom_webmercator, -5e6, 0) as the_geom_webmercator from test_table limit 2 offset 2',
+               cartocss: '#layer { marker-fill:blue; marker-allow-overlap:true; }', 
+               cartocss_version: '2.0.2' 
+             } }
+        ]
+      };
+
+      var expected_token = "d442ca6d3ece793b9c16c02a1d1ea5f2";
+      Step(
+        function do_post()
+        {
+          var next = this;
+          assert.response(server, {
+              url: '/tiles/layergroup',
+              method: 'POST',
+              headers: {host: 'localhost', 'Content-Type': 'application/json' },
+              data: JSON.stringify(layergroup)
+          }, {}, function(res) {
+              assert.equal(res.statusCode, 200, res.body);
+              var parsedBody = JSON.parse(res.body);
+              var expectedBody = { layergroupid: expected_token };
+              // TODO: check last modified
+              //expectedBody.layercount = 2;
+              if ( expected_token ) assert.deepEqual(parsedBody, expectedBody);
+              else expected_token = parsedBody.layergroupid;
+              next(null, res);
+          });
+        },
+        function do_get_tile(err)
+        {
+          if ( err ) throw err;
+          var next = this;
+          assert.response(server, {
+              url: '/tiles/layergroup/' + expected_token + '/0/0/0.png',
+              method: 'GET',
+              headers: {host: 'localhost' },
+              encoding: 'binary'
+          }, {}, function(res) {
+              assert.equal(res.statusCode, 200, res.body);
+              assert.equal(res.headers['content-type'], "image/png");
+              assert.imageEqualsFile(res.body, 'test/fixtures/test_table_0_0_0_multilayer1.png', 2,
+                function(err, similarity) {
+                  next(err);
+              });
+          });
+        },
+        function do_get_grid_layer0(err)
+        {
+          if ( err ) throw err;
+          var next = this;
+          assert.response(server, {
+              url: '/tiles/layergroup/' + expected_token
+                 + '/layer0/0/0/0.grid.json?interactivity=cartodb_id',
+              headers: {host: 'localhost' },
+              method: 'GET'
+          }, {}, function(res) {
+              assert.equal(res.statusCode, 200, res.body);
+              assert.equal(res.headers['content-type'], "text/javascript; charset=utf-8; charset=utf-8");
+              assert.utfgridEqualsFile(res.body, 'test/fixtures/test_table_0_0_0_multilayer1.layer0.grid.json', 2,
+                function(err, similarity) {
+                  next(err);
+              });
+          });
+        },
+        function do_get_grid_layer1(err)
+        {
+          if ( err ) throw err;
+          var next = this;
+          assert.response(server, {
+              url: '/tiles/layergroup/' + expected_token
+                 + '/layer1/0/0/0.grid.json?interactivity=cartodb_id',
+              headers: {host: 'localhost' },
+              method: 'GET'
+          }, {}, function(res) {
+              assert.equal(res.statusCode, 200, res.body);
+              assert.equal(res.headers['content-type'], "text/javascript; charset=utf-8; charset=utf-8");
+              assert.utfgridEqualsFile(res.body, 'test/fixtures/test_table_0_0_0_multilayer1.layer1.grid.json', 2,
+                function(err, similarity) {
+                  next(err);
+              });
+          });
+        },
+        function finish(err) {
+          var errors = [];
+          if ( err ) {
+            errors.push(err.message);
+            console.log("Error: " + err);
+          }
+          redis_client.keys("map_style|cartodb_test_user_1_db|~" + expected_token, function(err, matches) {
+              if ( err ) errors.push(err.message);
+              assert.equal(matches.length, 1, "Missing expected token " + expected_token + " from redis: " + matches);
+              redis_client.del(matches, function(err) {
+                if ( err ) errors.push(err.message);
+                if ( errors.length ) done(new Error(errors));
+                else done(null);
+              });
+          });
+        }
+      );
+    });
+
+    suiteTeardown(function(done) {
+        // This test will add map_style records, like
+        // 'map_style|null|publicuser|my_table',
+        redis_client.keys("map_style|*", function(err, matches) {
+            _.each(matches, function(k) { redis_client.del(k); });
+            done();
+        });
+    });
+    
+});
+
diff --git a/test/acceptance/server.js b/test/acceptance/server.js
index 7f5ccf03..3e419015 100644
--- a/test/acceptance/server.js
+++ b/test/acceptance/server.js
@@ -110,7 +110,7 @@ suite('server', function() {
         },{
         }, function(res) {
           // FIXME: should be 401 Unauthorized
-          assert.equal(res.statusCode, 500, res.body);
+          assert.equal(res.statusCode, 400, res.body);
           assert.deepEqual(JSON.parse(res.body),
             {error: 'Sorry, you are unauthorized (permission denied)'});
           done();
@@ -127,7 +127,7 @@ suite('server', function() {
         },{
         }, function(res) {
           // FIXME: should be 401 Unauthorized
-          assert.equal(res.statusCode, 500, res.body);
+          assert.equal(res.statusCode, 400, res.statusCode + ': ' + res.body);
           assert.deepEqual(JSON.parse(res.body),
             {error:"missing unknown_user's dbname in redis (try CARTODB/script/restore_redis)"});
           done();
@@ -175,7 +175,7 @@ suite('server', function() {
             headers: {host: 'localhost', 'Content-Type': 'application/x-www-form-urlencoded' },
             data: querystring.stringify({style: '#my_table3{backgxxxxxround-color:#fff;}'})
         },{
-            status: 500, // FIXME: should be 400 !
+            status: 400, 
             body: /Unrecognized rule: backgxxxxxround-color/
         }, function() { done(); });
     });
@@ -187,7 +187,7 @@ suite('server', function() {
             headers: {host: 'localhost', 'Content-Type': 'application/x-www-form-urlencoded' },
             data: querystring.stringify({style: '#my_table3{'})
         },{
-            status: 500, // FIXME: should be 400 !
+            status: 400, 
             body: /Missing closing/
         }, function() { done(); });
     });
@@ -199,7 +199,7 @@ suite('server', function() {
             headers: {host: 'localhost', 'Content-Type': 'application/x-www-form-urlencoded' },
             data: querystring.stringify({style: '#my_table4{backgxxxxxround-color:#fff;foo:bar}'})
         },{
-            status: 500, // FIXME: should be 400 !
+            status: 400, 
         }, function(res) {
           var parsed = JSON.parse(res.body);
           assert.equal(parsed.length, 2);
@@ -252,7 +252,7 @@ suite('server', function() {
               data: querystring.stringify({style: 'Map { background-color:#aaa; }'})
           },{}, function(res) {
             // FIXME: should be 401 Unauthorized
-            assert.equal(res.statusCode, 500, res.body);
+            assert.equal(res.statusCode, 400, res.statusCode + ': ' + res.body);
             assert.ok(res.body.indexOf('map state cannot be changed by unauthenticated request') != -1, res.body);
 
             assert.response(server, {
@@ -464,7 +464,7 @@ suite('server', function() {
             method: 'GET'
         },{}, function(res) {
           // FIXME: should be 401 Unauthorized
-          assert.equal(res.statusCode, 500, res.body);
+          assert.equal(res.statusCode, 500, res.statusCode + ': ' + res.body);
           done();
         });
     });
@@ -479,7 +479,7 @@ suite('server', function() {
         },{
         }, function(res) {
           // FIXME: should be 401 Unauthorized
-          assert.equal(res.statusCode, 500, res.body);
+          assert.equal(res.statusCode, 500, res.statusCode + ': ' + res.body);
           assert.deepEqual(JSON.parse(res.body),
             {error:"missing unknown_user's dbname in redis (try CARTODB/script/restore_redis)"});
           done();
diff --git a/test/support/assert.js b/test/support/assert.js
index 82fcf99d..26d3221f 100644
--- a/test/support/assert.js
+++ b/test/support/assert.js
@@ -8,6 +8,64 @@ var exec = require('child_process').exec;
 
 var assert = module.exports = exports = require('assert');
 
+// @param tolerance number of tolerated grid cell differences
+assert.utfgridEqualsFile = function(buffer, file_b, tolerance, callback) {
+    fs.writeFileSync('/tmp/grid.json', buffer, 'binary'); // <-- to debug/update
+    var expected_json = JSON.parse(fs.readFileSync(file_b, 'utf8'));
+
+    var err = null;
+
+    var Celldiff = function(x, y, ev, ov) {
+      this.x = x;
+      this.y = y;
+      this.ev = ev;
+      this.ov = ov;
+    };
+
+    Celldiff.prototype.toString = function() {
+      return '(' + this.x + ',' + this.y + ')["' + this.ev + '" != "' + this.ov + '"]';
+    };
+
+    try {
+      var obtained_json = JSON.parse(buffer);
+
+      // compare grid
+      var obtained_grid = obtained_json.grid;
+      var expected_grid = expected_json.grid;
+      var nrows = obtained_grid.length
+      if (nrows != expected_grid.length) {
+        throw new Error( "Obtained grid rows (" + nrows +
+                    ") != expected grid rows (" + expected_grid.length + ")" );
+      }
+      var celldiff = [];
+      for (var i=0; i<nrows; ++i) {
+        var ocols = obtained_grid[i];
+        var ecols = expected_grid[i];
+        var ncols = ocols.length;
+        if ( ncols != ecols.length ) {
+          throw new Error( "Obtained grid cols (" + ncols +
+                   ") != expected grid cols (" + ecols.length +
+                   ") on row " + i ); 
+        }
+        for (var j=0; j<ncols; ++j) {
+          var ocell = ocols[j];
+          var ecell = ecols[j];
+          if ( ocell !== ecell ) {
+            celldiff.push(new Celldiff(i, j, ecell, ocell));
+          }
+        }
+      }
+
+      if ( celldiff.length > tolerance ) {
+        throw new Error( celldiff.length + " cell differences: " + celldiff );
+      }
+
+      assert.deepEqual(obtained_json.keys, expected_json.keys);
+    } catch (e) { err = e; }
+
+    callback(err);
+};
+
 //
 // @param tol tolerated color distance as a percent over max channel value
 //            by default this is zero. For meaningful values, see
diff --git a/test/support/prepare_db.sh b/test/support/prepare_db.sh
index c5a39d7e..567b4d1e 100755
--- a/test/support/prepare_db.sh
+++ b/test/support/prepare_db.sh
@@ -33,4 +33,5 @@ echo "SADD rails:users:localhost:map_key 1235" | redis-cli -p ${REDIS_PORT} -n 5
 echo 'HSET rails:'"${TEST_DB}"':my_table infowindow "this, that, the other"' | redis-cli -p ${REDIS_PORT} -n 0
 echo 'HSET rails:'"${TEST_DB}"':test_table_private_1 privacy "0"' | redis-cli -p ${REDIS_PORT} -n 0
 
-echo "Finished preparing data. Run tests with expresso."
+echo "Finished preparing data. Ready to run tests"
+
diff --git a/tools/munin/Makefile b/tools/munin/Makefile
new file mode 100644
index 00000000..a1aa98b2
--- /dev/null
+++ b/tools/munin/Makefile
@@ -0,0 +1,19 @@
+MUNIN_PLUGINS_DIR=/etc/munin/plugins
+MUNIN_PLUGINS_CONFIG_DIR=/etc/munin/plugin-conf.d
+PWD=$(shell pwd)
+
+all: windshaft.conf
+
+windshaft.conf: windshaft.conf.in
+	sed 's#@PWD@#$(PWD)#' < $< > $@
+
+install-munin-plugin-conf: windshaft.conf 
+	install -m 644 $< $(MUNIN_PLUGINS_CONFIG_DIR)/windshaft.conf
+
+install-munin-plugin: windshaft
+	install -m 755 $< $(MUNIN_PLUGINS_DIR)/windshaft
+
+install: install-munin-plugin install-munin-plugin-conf
+
+clean:
+	rm -f windshaft.conf
diff --git a/tools/munin/windshaft b/tools/munin/windshaft
new file mode 100755
index 00000000..77adcb23
--- /dev/null
+++ b/tools/munin/windshaft
@@ -0,0 +1,87 @@
+#!/bin/sh
+
+envnik=$(basename "${TILER_ENVIRONMENT}" .js)
+
+if test "$1" = "config"; then
+echo "graph_title fd usage (${envnik})"
+cat <<"EOM"
+graph_vlabel number of file descriptors
+graph_category windshaft
+graph_scale no
+procs.label Number of tiler processes
+pgsql.label PostgreSQL connections (max)
+redis.label Redis connections (max)
+http.label Incoming http requests (max)
+caches.label Number of renderer caches (max)
+nfd.label Total file descriptors (max)
+EOM
+exit 0
+fi
+
+if test x"$1" != x; then
+  TILER_ENVIRONMENT=$(cd $(dirname $0); pwd)/../../config/environments/${1}.js
+fi
+
+if test -z "$TILER_ENVIRONMENT"; then
+  echo "Usage: $0 [<environment>]" >&2
+  echo "   or: [TILER_ENVIRONMENT=<environment>] $0" >&2
+  exit 1
+fi
+
+http_port=$(echo "console.log(require('${TILER_ENVIRONMENT}').port)" | node) || exit 1
+pgsql_port=$(echo "console.log(require('${TILER_ENVIRONMENT}').postgres.port)" | node) || exit 1
+redis_port=$(echo "console.log(require('${TILER_ENVIRONMENT}').redis.port)" | node) || exit 1
+
+pids=$(lsof -i :${http_port} | grep LISTEN | awk '{print $2}')
+nworkers=$(echo "${pids}" | wc -l)
+pids=$(echo "${pids}" | paste -sd ' ')
+
+if test -z "${pids}"; then
+  echo "No processes found listening on tcp port '${http_port}'" >&2
+  exit 1
+fi
+
+tmpreport="/tmp/checkfd.$$.txt"
+
+lsof -Pp $(echo "${pids}" | tr ' ' ',') > "${tmpreport}"
+
+maxdb=0
+maxredis=0
+maxhttp=0
+maxtot=0
+maxcache=0
+
+for pid in ${pids}; do
+
+  cnt=$(grep "${pid}" "${tmpreport}" | grep ":${pgsql_port} " | wc -l);
+  if test $cnt -gt $maxdb; then maxdb=$cnt; fi
+  
+  cnt=$(grep "${pid}" "${tmpreport}" | grep ":${redis_port} " | wc -l);
+  if test $cnt -gt $maxredis; then maxredis=$cnt; fi
+
+  cnt=$(grep "${pid}" "${tmpreport}" | grep ":${http_port}-" | grep -v "LISTEN" | wc -l);
+  if test $cnt -gt $maxhttp; then maxhttp=$cnt; fi
+
+  cnt=$(grep "${pid}" "${tmpreport}" | wc -l);
+  if test $cnt -gt $maxtot; then maxtot=$cnt; fi
+
+  log=$(grep "${pid}" "${tmpreport}" | grep -w 1w | awk '{print $9}')
+  if test -e "${log}"; then
+    kill -USR1 "${pid}"
+    cnt=$(tac ${log} | sed -n -e '/ItemKey/p;/^RenderCache/q' | wc -l)
+    if test $cnt -gt $maxcache; then maxcache=$cnt; fi
+  else
+    # report the error...
+    maxcache=-1
+  fi
+
+done
+
+echo "procs.value ${nworkers}"
+echo "pgsql.value ${maxdb}"
+echo "redis.value ${maxredis}"
+echo "http.value ${maxhttp}"
+echo "caches.value ${maxcache}"
+echo "nfd.value ${maxtot}"
+
+rm -f "${tmpreport}"
diff --git a/tools/munin/windshaft.conf.in b/tools/munin/windshaft.conf.in
new file mode 100644
index 00000000..0e71f467
--- /dev/null
+++ b/tools/munin/windshaft.conf.in
@@ -0,0 +1,5 @@
+# Configuration file for munin plugin
+
+[windshaft]
+user root
+env.TILER_ENVIRONMENT @PWD@/../../config/environments/production.js