I believe this should be happening for every CDM probe out there, otherwise i have a serious problem with all the Linux distros in my customer's environment (RHEL and CentOs).
CDM is reporting disk percentage used or free based on disk size alone, ignoring the fact that there is a reservation space made in linux file systems, when not specified otherwise.
This is causing some desbelief issues, as the customer stating that Zabbix is better than CA UIM in every other way, because of such simple monitoring taks not working properly.
We tried the raw configure option in CDM probe where you can type "Yes" for an option called "Use disk system values", and then you think it's fine but it isn't. It becomes clear that there is something wrong (maybe a hard coded usage %).
On low disk % you might ignore the 1% difference, but when you get disks with more used space, you'll start seeing that things are not what should be, with higher rates of % difference between the Linux System and what is being shown on CA UIM.
If there is an easy solution for that, or anyone else can confirm or help, thanks in advance.
I'll open a case for that also.