Is it possible to set up a condition for the cdm probe to monitor when disk space falls to 10% free disk space AND has 2 GB remaining?
I don't think you can alert when both conditions are meant from the probe itself but you could alert on the less than 2gigs free then write a preprocess script to look in the messages for the percentage may have to do regex to get that value but then you can compare it if less than ten alert if not just change the level to 0.
We use a custom disk profile (in the Custom Tab) to do something similar to this, we raise alerts at 10% and 20% free and then raise a Critical alert at a specific free space in GB that is set at a value at which space becomes service affecting, i.e. we have a minor alert at 20%, a major alert at 10% and a critical alert at 1 GB
I did a nice little trick a while back for <10% and less than 1Gb. I simply filtered out the messages with Gb in them as once it drops below a gig you get messages like "... free space of 999Mb ... "