diff --git a/setup/start/collectd/collectd.conf b/setup/start/collectd/collectd.conf
index fa531d23f..75d559f8b 100644
--- a/setup/start/collectd/collectd.conf
+++ b/setup/start/collectd/collectd.conf
@@ -243,8 +243,19 @@ LoadPlugin write_graphite
 
     Import "du"
     <Module du>
-        Path boxdata "/home/yellowtent/boxdata"
-        Path platformdata "/home/yellowtent/platformdata"
+        <Path>
+            Instance maildata
+            Dir "/home/yellowtent/boxdata/mail"
+        </Path>
+        <Path>
+            Instance boxdata
+            Dir "/home/yellowtent/boxdata"
+            Exclude "mail"
+        </Path>
+        <Path>
+            Instance platformdata
+            Dir "/home/yellowtent/platformdata"
+        </Path>
     </Module>
 </Plugin>
 
diff --git a/setup/start/collectd/du.py b/setup/start/collectd/du.py
index cebff1aef..ed3b9d8ad 100644
--- a/setup/start/collectd/du.py
+++ b/setup/start/collectd/du.py
@@ -1,39 +1,55 @@
-import collectd,os,subprocess
+import collectd,os,subprocess,sys
 
 # https://www.programcreek.com/python/example/106897/collectd.register_read
 
-PATHS = []
-INTERVAL = 60 * 60 * 24
+PATHS = [] # { name, dir, exclude }
+INTERVAL = 60 * 60 * 24 # every day
 
-def du(path):
-    return subprocess.check_output(['du','-Dsb', path]).split()[0].decode('utf-8')
+def du(pathinfo):
+    cmd = 'timeout 1800 du -Dsb "{}"'.format(pathinfo['dir'])
+    if pathinfo['exclude'] != '':
+        cmd += ' --exclude "{}"'.format(pathinfo['exclude'])
 
-def init():
-    global PATHS
-    collectd.info('custom du plugin initialized with %s' % PATHS)
+    collectd.info('computing size with command: %s' % cmd);
+    try:
+        size = subprocess.check_output(cmd, shell=True).split()[0].decode('utf-8')
+        collectd.info('\tsize of %s is %s' % (pathinfo['dir'], size))
+        return size
+    except Exception as e:
+        collectd.info('\terror getting the size of %s: %s' % (pathinfo['dir'], str(e)))
+        return -1
 
-# configure is called for each module block
+# configure is called for each module block. this is called before init
 def configure(config):
     global PATHS
 
-    for node in config.children:
-        key = node.key
-
-        if key == 'Path':
-            PATHS.append({ 'name': node.values[0], 'path': node.values[1] })
-            collectd.info('du plugin: monitoring %s' % node.values[1])
-        else:
+    for child in config.children:
+        if child.key != 'Path':
             collectd.info('du plugin: Unknown config key "%s"' % key)
+            continue
+
+        pathinfo = { 'name': '', 'dir': '', 'exclude': '' }
+        for node in child.children:
+            if node.key == 'Instance':
+                pathinfo['name'] = node.values[0]
+            elif node.key == 'Dir':
+                pathinfo['dir'] = node.values[0]
+            elif node.key == 'Exclude':
+                pathinfo['exclude'] = node.values[0]
+
+        PATHS.append(pathinfo);
+        collectd.info('du plugin: monitoring %s' % pathinfo['dir']);
+
+def init():
+    global PATHS
+    collectd.info('custom du plugin initialized with %s %s' % (PATHS, sys.version))
 
 def read():
-    for p in PATHS:
-        path = p['path']
-        collectd.info('computing size of %s' % path)
-        size = du(path)
-        collectd.info('du plugin: size of %s is %s' % (path, size))
+    for pathinfo in PATHS:
+        size = du(pathinfo)
 
         # type comes from https://github.com/collectd/collectd/blob/master/src/types.db
-        val = collectd.Values(type='capacity', plugin='du', plugin_instance=p['name'])
+        val = collectd.Values(type='capacity', plugin='du', plugin_instance=pathinfo['name'])
 
         val.dispatch(values=[size], type_instance='usage')
 
diff --git a/src/cloudron.js b/src/cloudron.js
index 9d60201e3..a52cd64d0 100644
--- a/src/cloudron.js
+++ b/src/cloudron.js
@@ -185,6 +185,7 @@ function getDisks(callback) {
         const disks = {
             disks: ext4Disks, // root disk is first
             boxDataDisk: values[1].filesystem,
+            mailDataDisk: values[1].filesystem,
             platformDataDisk: values[2].filesystem,
             appsDataDisk: values[3].filesystem,
             apps: {}
diff --git a/src/collectd.config.ejs b/src/collectd.config.ejs
index 2d72edab0..ab5d2ce49 100644
--- a/src/collectd.config.ejs
+++ b/src/collectd.config.ejs
@@ -33,7 +33,10 @@ LoadPlugin "table"
 
 <Plugin python>
   <Module du>
-    Path "<%= appId %>" "<%= appDataDir %>"
+    <Path>
+        Instance "<%= appId %>"
+        Dir "<%= appDataDir %>"
+    </Path>
   </Module>
 </Plugin>