I am running into an issue when monitoring disk space on a centos 5 machine, on the cli after running the df command I get the following:

[tracking1] ~ # df -H
Filesystem                                        Size   Used  Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00       2.0T   1.8T    67G  97% /
/dev/sda1                                        104M    12M    87M  12% /boot
tmpfs                                                 4.3G      0   4.3G   0% /dev/shm

But SNMP/Zenoss reports

Mount	Total bytes	Used bytes	Free bytes	% Util	M	Lock
	/	1.7TB	1.6TB	154.4GB	91
	/boot	98.7MB	10.7MB	88.0MB	10

Is this just me or is someone else seeing inconsistent data also.

Thanks in advance.