diff --git a/README.md b/README.md
index 10ce3e5..c78bce5 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,20 @@
 # py_check_redis
+
+
+Add redis user with these permissions:
+```
+-@all +info +ping
+```
+
+Plugin checks backup nodes automatically for being readonly and connection to master, ie:
+```
+master_link_status:up
+slave_read_only:1
+```
+
+Number of expected replicas on a master is configurable, ie:
+```
+check_redis.py -u monitoring -P $(/usr/bin/cat /etc/check_redis_auth) --backup_nodes=1
+```
+
+Or omit the ```--backup_nodes``` flag for a standalone/single instance.
diff --git a/check_redis.py b/check_redis.py
index 6529336..59794ed 100644
--- a/check_redis.py
+++ b/check_redis.py
@@ -3,19 +3,22 @@
 
 import redis
 import sys
+import re
 from optparse import OptionParser
 
 
 class NagiosRedis(object):
 
-    def __init__(self, host, port, password, bdname):
+    def __init__(self, host, port, username, password, dbname, backup_nodes):
         self.host = host
+        self.username = username
         self.password = password
         self.port = port
-        self.dbname = bdname
+        self.dbname = dbname
+        self.backup_nodes = backup_nodes
 
         try:
-            self.conn = redis.Redis(host=self.host, port=self.port, password=self.password, socket_timeout=1)
+            self.conn = redis.Redis(host=self.host, port=self.port, username=self.username, password=self.password, socket_timeout=1)
             self.info_out = self.conn.info()
             self.conn.ping()
 
@@ -43,6 +46,26 @@ def get_used_memory(self):
 
         return "used_memory_human: %s" % self.info_out['used_memory_human']
 
+    def get_role(self):
+
+        return "role: %s" % self.info_out['role']
+
+    def get_connected_backups(self):
+
+        return "connected_backups: %s" % self.info_out['connected_slaves']
+
+    def get_mls(self):
+
+        return "master_link_status: %s" % self.info_out['master_link_status']
+
+    def get_ro(self):
+
+        return "slave_read_only: %s" % self.info_out['slave_read_only']
+
+    def get_master(self):
+
+        return "master_host: %s" % self.info_out['master_host']
+
     def nagios_check(self):
         number_keys = ''
         version = self.get_version()
@@ -51,11 +74,26 @@ def nagios_check(self):
             number_keys = self.get_number_keys()
         memory = self.get_used_memory()
         uptime = self.get_uptime()
+        role = self.get_role()
+        replicas = self.get_connected_backups()
+        replica_count = int(re.sub('\D', '', replicas))
+        backup_nodes = int(self.backup_nodes)
+        if 'master' in role:
+            if replica_count != backup_nodes:
+                print('REDIS CRITICAL - %s, %s' % (replicas, role))
+                sys.exit(2)
+        if 'slave' in role:
+            mls = self.get_mls()
+            ro = self.get_ro()
+            master = self.get_master()
+            if 'up' not in mls or '1' not in ro:
+                print('REDIS CRITICAL - %s, %s, %s, %s' % (role, mls, ro, master))
+                sys.exit(2)
         if number_keys == '':
-            print('OK REDIS No keys, %s, %s, %s' % (version, memory, uptime))
+            print('OK REDIS No keys, %s, %s, %s, %s' % (version, memory, uptime, role))
             sys.exit(0)
         else:
-            print('OK REDIS %s, %s, %s, %s, %s' % (version, client_connected, number_keys, memory, uptime))
+            print('OK REDIS %s, %s, %s, %s, %s, %s' % (version, client_connected, number_keys, memory, uptime, role))
             sys.exit(0)
 
 
@@ -65,10 +103,12 @@ def build_parser():
     :return: parser config
     """
     parser = OptionParser(usage="usage: %prog [options]", version="%prog 1.0")
-    parser.add_option("-H", "--host", dest="host", help="Redis server to connect to.", default=False)
+    parser.add_option("-H", "--host", dest="host", help="Redis server to connect to.", default='127.0.0.1')
     parser.add_option("-p", "--port", dest="port", help="Redis port to connect to.", type="int", default=6379)
+    parser.add_option("-u", "--username", dest="username", help="Redis username.",  default='default')
     parser.add_option("-P", "--password", dest="password", help="Redis password to connect to.",  default='')
     parser.add_option("-d", "--dbname", dest="dbname", help="Redis database name, default is db0", default='db0')
+    parser.add_option("-b", "--backup_nodes", dest="backup_nodes", help="Number of connected backup nodes to check for",  default=0)
     parser.add_option("-t", "--timeout", dest="timeout",
                       help="Number of milliesconds to wait before timing out and considering redis down",
                       type="int", default=2000)
@@ -85,5 +125,5 @@ def build_parser():
         sys.exit(0)
 
     else:
-        server = NagiosRedis(options.host, options.port, options.password, options.dbname)
+        server = NagiosRedis(options.host, options.port, options.username, options.password, options.dbname, options.backup_nodes)
         server.nagios_check()