The Free Disk Space % alert notifies you when its configured condition is met on SQL Server instances so you can investigate and respond.
Mini DBA describes this alert as: Free disk space % has fallen below a certain threshold This may mean that the drive will fill completely and the server will not be able to function correctly Mini DBA evaluates this alert once a minute so changes are detected quickly.
This alert protects storage and recovery capacity. It helps you find growth, retention, and backup conditions that can stop writes, break recovery objectives, or leave the server without enough working space for normal database activity.
Enable it once the instance has a normal workload baseline. It is especially useful on busy OLTP, reporting, and integration systems where resource pressure can quickly become user-visible.
Threshold meaning: % free. Major threshold: 2 %. Minor threshold: 10 %. Comparison direction: under. For an under-threshold alert, increasing a threshold makes that severity fire sooner; decreasing it waits until the value falls further. Set the minor threshold as an early-warning level and the major threshold at the lowest acceptable value for the service.
Free space by removing safe-to-delete files, expanding the volume or tablespace, moving growth-heavy objects, correcting retention settings, or shrinking only after a documented one-off event. For recovery-related areas, verify that backups and log shipping or archiving are healthy before deleting anything.
Storage alerts should usually stay enabled even on quiet systems because the impact of missing them is high. Tune warning thresholds to leave enough time for approval, provisioning, and validation, especially when storage changes are handled by another infrastructure team.