This configuration parameter specifies a threshold percentage of disk space that is added to the minimum percentage of disk space (set in the spool.diskspace.min parameter) that determines when the information/warning/error log state is reset. Message logging resumes only after the log state is reset.
When disk space drops below the minimum percentage (for example, 10%), a warning is logged. Additional warnings are not logged until disk space has risen above the minimum percentage + threshold percentage (for example, 10% + 2% = 12%), and then drops again below the minimum percentage (10%).
Setting a threshold percentage is useful to prevent unnecessary log messages when disk space hovers near the minimum percentage and would otherwise trigger a log message every time the minimum percentage is crossed.
The default value is 2 percent of disk space.
You can also set this parameter using group policy.