Nagios Support Forum

I just installed Nagios XI and setup the Linux Agent on one of my servers. As soon as it started monitoring the server it started complaining about / Disk Usage being critical.

Here is the message that it displayed "DISK CRITICAL - free space: / 12647 MB (71% inode=97%):"

But looking directly at the server this is what I found:

df -i
Filesystem Inodes IUsed IFree IUse% Mounted on
/dev/mapper/VolGroup00-LogVol00 4943136 136229 4806907 3% /
/dev/xvda1 26104 46 26058 1% /boot
tmpfs 524288 1 524287 1% /dev/shm
/usr/tmpDSK 128016 7669 120347 6% /tmp
/dev/mapper/Home-lvol0 524283904 197550 524086354 1% /home

df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00 19G 5.0G 13G 29% /
/dev/xvda1 99M 21M 73M 23% /boot
tmpfs 2.0G 0 2.0G 0% /dev/shm
/usr/tmpDSK 485M 202M 258M 44% /tmp
/dev/mapper/Home-lvol0 500G 8.8G 492G 2% /home


Looking at the numbers it looks like it is actually reading it backwards. If this is the case should I just invert the command?

ie: check_nrpe!check_disk!-a '-w 80% -c 90% -p /' to check_nrpe!check_disk!-a '-w 20% -c 10% -p /'?

Yes. From the check_disk help text to confirm:

-w, --warning=PERCENT%
Exit with WARNING status if less than PERCENT of disk space is free
-c, --critical=PERCENT%
Exit with CRITCAL status if less than PERCENT of disk space is free
-W, --iwarning=PERCENT%
Exit with WARNING status if less than PERCENT of inode space is free
-K, --icritical=PERCENT%
Exit with CRITICAL status if less than PERCENT of inode space is free

Was there something misleading in our code/documentation that we need to fix, or would you describe this as user error?

I created that host profile using the Linux Server wizard. The values it used for the '/' folder was "check_nrpe!check_disk!-a '-w 80% -c 90% -p /'" which is obviously incorrect.

Rerunning the wizard states "Path: Warning Usage: % Critical Usage: %" for the values. The default entries for this are 80% and 90%. According to the wording there that is correct. But as you said the help text uses the values in reverse.

Also I have tried to change the values both in Nagios and Core Config Manager, but it does not change the values. I will probably end up having to delete the whole host and redo it.

I opened a tracker ticket for this at http://tracker.nagios.com/view.php?id=55

For changing the values, where did you try to change them? I suspect they're right in the "check command" listed in the Core Config Manager, right?

First I tried to change it directly in the Nagios > Service Detail. Then clicking on the service > Configure > Re-Configure this service.
Tried to change: check_nrpe!check_disk!-a '-w 80% -c 90% -p /' to check_nrpe!check_disk!-a '-w 20% -c 10% -p /'.
It says that it changed it but looking back at it the values are unchanged.

Second I tried to change it in NCCM > Services > Modify.
Tried to change: $ARG2$ = -a '-w 80% -c 90% -p /' to $ARG2$ = -a '-w 20% -c 10% -p'.
Ran in to the same issue.

Looking back at it I figured that the /' was what was causing it to not take. I tried the same process but with / '. Configuring directly in Nagios still failed, but I was able to make the change in NCCM.