Resolves #207 - Report disk space metrics for root

Author: Steve Ramage

conf/etc/collectd/collectd.conf

@@ -293,8 +293,10 @@ LoadPlugin write_graphite
 #</Plugin>
 
 <Plugin df>
-	Device "/dev/vda"
+	MountPoint "/"
 	ReportInodes true
+	ValuesAbsolute true
+	IgnoreSelected false
 #	Device "/dev/sda1"
 #	Device "192.168.0.2:/mnt/nfs"
 #	MountPoint "/home"