diff --git a/shinken/misc/perfdata.py b/shinken/misc/perfdata.py
index 6e7a4c7dbb..9ed4c2261e 100755
--- a/shinken/misc/perfdata.py
+++ b/shinken/misc/perfdata.py
@@ -34,6 +34,8 @@
         '^([^=]+)=([\d\.\-\+eE]+)([\w\/%]*)'
         ';?([\d\.\-\+eE:~@]+)?;?([\d\.\-\+eE:~@]+)?;?([\d\.\-\+eE]+)?;?([\d\.\-\+eE]+)?;?\s*'
     )
+quote_pattern = re.compile("^'(.+)'$")
+replace1_pattern = re.compile('\1')
 
 
 # If we can return an int or a float, or None
@@ -54,29 +56,34 @@ def __init__(self, s):
         # print "Analysis string", s
         r = metric_pattern.match(s)
         if r:
-            # Get the name but remove all ' in it
-            self.name = r.group(1).replace("'", "")
+            # Strip outer quotes, and replace double quotes with single
+            self.name = re.sub(r"^'(.+)'$", r'\1', r.group(1)).replace("''", "'")
             self.value = guess_int_or_float(r.group(2))
             self.uom = r.group(3)
             self.warning = guess_int_or_float(r.group(4))
             self.critical = guess_int_or_float(r.group(5))
-            self.min = guess_int_or_float(r.group(6))
-            self.max = guess_int_or_float(r.group(7))
+            self.min = self.min_supplied = guess_int_or_float(r.group(6))
+            self.max = self.max_supplied = guess_int_or_float(r.group(7))
             # print 'Name', self.name
             # print "Value", self.value
             # print "Res", r
             # print r.groups()
             if self.uom == '%':
-                self.min = 0
-                self.max = 100
+                self.min = 0 if self.min is None else self.min
+                self.max = 100 if self.max is None else self.max
 
     def __str__(self):
-        s = "%s=%s%s" % (self.name, self.value, self.uom)
-        if self.warning:
-            s = s + ";%s" % (self.warning)
-        if self.critical:
-            s = s + ";%s" % (self.critical)
-        return s
+        # Restore double quotes in nae
+        name = self.name.replace("'", "''")
+        # Quote whole name if it contains a space
+        if " " in name:
+            name = "'" + name + "'"
+        min = self.min_supplied
+        max = self.max_supplied
+        components = ["%s=%s%s" % (name, self.value, self.uom), self.warning, self.critical, min, max]
+        while components[-1] is None:
+            components.pop()
+        return ";".join(map(lambda v: "" if v is None else str(v), components))
 
 
 class PerfDatas:
@@ -101,3 +108,4 @@ def __getitem__(self, key):
 
     def __contains__(self, key):
         return key in self.metrics
+
diff --git a/test/test_parse_perfdata.py b/test/test_parse_perfdata.py
index 033a42f9dd..18933dd66c 100644
--- a/test/test_parse_perfdata.py
+++ b/test/test_parse_perfdata.py
@@ -45,16 +45,6 @@ def test_parsing_perfdata(self):
         self.assertEqual(0, m.min)
         self.assertEqual(1982, m.max)
 
-        s = 'ramused=90%;85;95;;'
-        m = Metric(s)
-        self.assertEqual('ramused', m.name)
-        self.assertEqual(90, m.value)
-        self.assertEqual('%', m.uom)
-        self.assertEqual(85, m.warning)
-        self.assertEqual(95, m.critical)
-        self.assertEqual(0, m.min)
-        self.assertEqual(100, m.max)
-
         s = 'ramused=1009MB;;;0;1982 swapused=540MB;;;; memused=90%'
         p = PerfDatas(s)
         p.metrics
@@ -78,26 +68,6 @@ def test_parsing_perfdata(self):
 
         self.assertEqual(3, len(p))
 
-        s = "'Physical Memory Used'=12085620736Bytes; 'Physical Memory Utilisation'=94%;80;90;"
-        p = PerfDatas(s)
-        p.metrics
-        m = p['Physical Memory Used']
-        self.assertEqual('Physical Memory Used', m.name)
-        self.assertEqual(12085620736, m.value)
-        self.assertEqual('Bytes', m.uom)
-        self.assertIs(None, m.warning)
-        self.assertIs(None, m.critical)
-        self.assertIs(None, m.min)
-        self.assertIs(None, m.max)
-
-        m = p['Physical Memory Utilisation']
-        self.assertEqual('Physical Memory Utilisation', m.name)
-        self.assertEqual(94, m.value)
-        self.assertEqual('%', m.uom)
-        self.assertEqual(80, m.warning)
-        self.assertEqual(90, m.critical)
-        self.assertEqual(0, m.min)
-        self.assertEqual(100, m.max)
 
         s = "'C: Space'=35.07GB; 'C: Utilisation'=87.7%;90;95;"
         p = PerfDatas(s)
@@ -147,6 +117,118 @@ def test_parsing_perfdata(self):
         p = PerfDatas(s)
         self.assertEqual(len(p), 0)
 
+    def test_parsing_perfdata_percentages(self):
+        # Test default min and max automatically supplied
+        s = 'ramused=90%;85;95;;'
+        m = Metric(s)
+        self.assertEqual('ramused', m.name)
+        self.assertEqual(90, m.value)
+        self.assertEqual('%', m.uom)
+        self.assertEqual(85, m.warning)
+        self.assertEqual(95, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(100, m.max)
+        #
+        # Test non-default min and max are handled
+        s = 'ramused=90%;85;95;10;95'
+        m = Metric(s)
+        self.assertEqual('ramused', m.name)
+        self.assertEqual(90, m.value)
+        self.assertEqual('%', m.uom)
+        self.assertEqual(85, m.warning)
+        self.assertEqual(95, m.critical)
+        self.assertEqual(10, m.min)
+        self.assertEqual(95, m.max)
+        #
+        # Test non-default min and max as floats are handled
+        s = 'ramused=90%;85;95;10.5;95.3'
+        m = Metric(s)
+        self.assertEqual('ramused', m.name)
+        self.assertEqual(90, m.value)
+        self.assertEqual('%', m.uom)
+        self.assertEqual(85, m.warning)
+        self.assertEqual(95, m.critical)
+        self.assertEqual(10.5, m.min)
+        self.assertEqual(95.3, m.max)
+
+    def test_parsing_perfdata_spaces(self):
+        s = "'Physical Memory Used'=12085620736Bytes; 'Physical Memory Utilisation'=94%;80;90;"
+        p = PerfDatas(s)
+        p.metrics
+        m = p['Physical Memory Used']
+        self.assertEqual('Physical Memory Used', m.name)
+        self.assertEqual(12085620736, m.value)
+        self.assertEqual('Bytes', m.uom)
+        self.assertIs(None, m.warning)
+        self.assertIs(None, m.critical)
+        self.assertIs(None, m.min)
+        self.assertIs(None, m.max)
+
+        m = p['Physical Memory Utilisation']
+        self.assertEqual('Physical Memory Utilisation', m.name)
+        self.assertEqual(94, m.value)
+        self.assertEqual('%', m.uom)
+        self.assertEqual(80, m.warning)
+        self.assertEqual(90, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(100, m.max)
+
+    def test_parsing_perfdata_quotes(self):
+        # Make sure outer quuotes get stripped, with or without space in name
+        s = "'ramused'=1009MB;;;0;1982 'ram is  used'=1009MB;;;0;1982"
+        p = PerfDatas(s)
+        m = p['ramused']
+        self.assertEqual('ramused', m.name)
+        self.assertEqual(1009, m.value)
+        self.assertEqual('MB', m.uom)
+        self.assertEqual(None, m.warning)
+        self.assertEqual(None, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(1982, m.max)
+
+        m = p['ram is  used']
+        self.assertEqual('ram is  used', m.name)
+        self.assertEqual(1009, m.value)
+        self.assertEqual('MB', m.uom)
+        self.assertEqual(None, m.warning)
+        self.assertEqual(None, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(1982, m.max)
+
+        # Confirm double quotes replace by single
+        s = "ram''used=1009MB;;;0;1982"
+        p = PerfDatas(s)
+        m = p["ram'used"]
+        self.assertEqual("ram'used", m.name)
+        self.assertEqual(1009, m.value)
+        self.assertEqual('MB', m.uom)
+        self.assertEqual(None, m.warning)
+        self.assertEqual(None, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(1982, m.max)
+
+        s = "ram''used''=1009MB;;;0;1982"
+        p = PerfDatas(s)
+        m = p["ram'used'"]
+        self.assertEqual("ram'used'", m.name)
+        self.assertEqual(1009, m.value)
+        self.assertEqual('MB', m.uom)
+        self.assertEqual(None, m.warning)
+        self.assertEqual(None, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(1982, m.max)
+
+        s = "ram'''used''=1009MB;;;0;1982"
+        p = PerfDatas(s)
+        m = p["ram''used'"]
+        self.assertEqual("ram''used'", m.name)
+        self.assertEqual(1009, m.value)
+        self.assertEqual('MB', m.uom)
+        self.assertEqual(None, m.warning)
+        self.assertEqual(None, m.critical)
+        self.assertEqual(0, m.min)
+        self.assertEqual(1982, m.max)
+
 if __name__ == '__main__':
     unittest.main()
 
diff --git a/test/test_string_perfdata.py b/test/test_string_perfdata.py
new file mode 100644
index 0000000000..629138ed50
--- /dev/null
+++ b/test/test_string_perfdata.py
@@ -0,0 +1,94 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (C) 2009-2014:
+#    Gabes Jean, naparuba@gmail.com
+#    Gerhard Lausser, Gerhard.Lausser@consol.de
+#
+# This file is part of Shinken.
+#
+# Shinken is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Shinken is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with Shinken.  If not, see <http://www.gnu.org/licenses/>.
+
+#
+# This file is used to test reading and processing of config files
+#
+
+from shinken_test import *
+from shinken.misc.perfdata import Metric, PerfDatas
+
+
+class TestStringPerfdata(ShinkenTest):
+    # Uncomment this is you want to use a specific configuration
+    # for your test
+    #def setUp(self):
+    #    self.setup_with_file('etc/shinken_parse_perfdata.cfg')
+
+    def test_string_all_four(self):
+        self.assertEqual('ramused=1009MB;1;2;3;4', str(Metric('ramused=1009MB;1;2;3;4')))
+
+    def test_string_drop_empty_from_end(self):
+        self.assertEqual('ramused=1009MB', str(Metric('ramused=1009MB')))
+        self.assertEqual('ramused=1009MB;1', str(Metric('ramused=1009MB;1')))
+        self.assertEqual('ramused=1009MB;1;2', str(Metric('ramused=1009MB;1;2')))
+        self.assertEqual('ramused=1009MB;1;2;3', str(Metric('ramused=1009MB;1;2;3')))
+        self.assertEqual('ramused=1009MB;1;2;3;4', str(Metric('ramused=1009MB;1;2;3;4')))
+
+    def test_string_empty_for_None(self):
+        self.assertEqual('ramused=1009MB', str(Metric('ramused=1009MB;')))
+        self.assertEqual('ramused=1009MB', str(Metric('ramused=1009MB;;')))
+        self.assertEqual('ramused=1009MB', str(Metric('ramused=1009MB;;;')))
+        self.assertEqual('ramused=1009MB', str(Metric('ramused=1009MB;;;;')))
+
+        self.assertEqual('ramused=1009MB;;2', str(Metric('ramused=1009MB;;2')))
+        self.assertEqual('ramused=1009MB;;;3', str(Metric('ramused=1009MB;;;3')))
+        self.assertEqual('ramused=1009MB;;;;4', str(Metric('ramused=1009MB;;;;4')))
+
+        self.assertEqual('ramused=1009MB;;2;;4', str(Metric('ramused=1009MB;;2;;4')))
+
+    def test_string_zero_preserved(self):
+        self.assertEqual('ramused=1009MB;0', str(Metric('ramused=1009MB;0')))
+        self.assertEqual('ramused=1009MB;;0', str(Metric('ramused=1009MB;;0')))
+        self.assertEqual('ramused=1009MB;;;0', str(Metric('ramused=1009MB;;;0')))
+        self.assertEqual('ramused=1009MB;;;;0', str(Metric('ramused=1009MB;;;;0')))
+
+    def test_string_percent_minmaxdefault_0_100(self):
+        # If not specified, defaults of 0 and 100 for min/max should not come back
+        self.assertEqual('utilization=80%;90;95', str(Metric('utilization=80%;90;95')))
+        self.assertEqual('utilization=80%;90;95;;', str(Metric('utilization=80%;90;95')) + ";;")
+
+    def test_string_percent_minmax_echo(self):
+        # Defined values of min max should come back always, even if defaults
+        self.assertEqual('utilization=80%;50;75;0;100', str(Metric('utilization=80%;50;75;0;100')))
+        self.assertEqual('utilization=80%;50;75;0', str(Metric('utilization=80%;50;75;0')))
+        self.assertEqual('utilization=80%;50;75;;100', str(Metric('utilization=80%;50;75;;100')))
+
+        # Same tests with non-default values
+        self.assertEqual('utilization=80%;50;75;85;95', str(Metric('utilization=80%;50;75;85;95')))
+        self.assertEqual('utilization=80%;50;75;85', str(Metric('utilization=80%;50;75;85')))
+        self.assertEqual('utilization=80%;50;75;;95', str(Metric('utilization=80%;50;75;;95')))
+
+    def test_string_quoted_names(self):
+        self.assertEqual("ram''used''=10", str(Metric("ram''used''=10")))
+        self.assertEqual("ram''used=10", str(Metric("ram''used=10")))
+        # Outer quotes present but not necessary should be stripped on format
+        self.assertEqual("ram''used=10", str(Metric("'ram''used'=10")))
+        # But not so if there is also a space
+        self.assertEqual("'ram was ''used'=10", str(Metric("'ram was ''used'=10")))
+
+        # String missing required outer quotes, should come back quoted
+        # This is debatable as it basically is an invalid metric/perfdata
+        self.assertEqual("'ram  ''used'''=10", str(Metric("ram  ''used''=10")))
+
+if __name__ == '__main__':
+    unittest.main()
+