[collectd] how is threshold working ?

[adnane]

I read all the doc in the site but still can't figure out how it works, 
should I see notifications in messages file ?

here is my configuration, i've changed it a lot but nothing seems to 
work I guess i'am missing something

   cat collectd.d/threshold.conf
LoadPlugin "Threshold"
<Plugin "threshold">
   <Host "nimporte">
       <Type "df">
         DataSource "free"
        WarningMin 80
         FailureMin 90
         Percentage true
         Persist true
       </Type>

     <Plugin "load">
       <Type "load">
         Instance "shirterm"
         WarningMax 1
         Persist true
         </Type>
     </Plugin>

     <Plugin "memory">
       <Type "memory">
         Instance "free"
         WarningMin 10000
         Persist true
         </Type>
     </Plugin>
  </Host>
</Plugin>


cat collectd.d/exec.conf
LoadPlugin "exec"
<Plugin exec>
         NotificationExec "collectd:collectd" 
"/usr/local/monitoring/collectd/etc/collectd-notify.sh"
  </Plugin>

ls -l collectd-notify.sh
-rwxr-xr-x 1 collectd collectd 74 Jul 22 12:54 collectd-notify.sh
[root at nimporte etc]# # cat collectd-notify.sh
#!/bin/bash

echo "`date` warning plugin df" >> /home/collectd/warn.txt

help please!