(A) The alarm “Databases - Data File Group Space Used”
1. This alarm tells you in % how full the Data File Group is.
2. This alarm evaluates the data file with autogrowth "and" non-autogrowth.
3. This alarm looks at the maximum size the files can get to and compares it to how full it is now. So if it’s a non-autogrow file, then that’s just the current size of the file.
(B) The alarm “Databases - Dynamic Data File Group Growths Remaining”
1. This alarm tells you how much growth is left.
2. This alarm evaluates the data file with autogrowth ONLY.
3. This alarm calculates how many more times the file group could grow before hitting the defined limits. If there are no autogrow files in the file group the growths remaining is set to null and therefore the alarm is ignored. Really it’s telling you that either you are running out of disk space for the files to keep growing into, or you are approaching the maximum file size (if it is set).