This alert is raised when the percentage of segment host disk space in use exceeds the percentage specified in the alert rule. The master disk space is not included in the calculation. The alert is raised once a day until the percentage drops below the percentage in the alert rule.
This alert warns you so that you can add disk storage or free up storage in order to prevent a catastrophic disk full error that could interrupt Greenplum Database service.
Here are some suggestions for freeing space on Greenplum Database hosts.