The Buffer Hit Ratio 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: The percentage of reads that use the buffer cache, if dipped below will trigger the alert Mini DBA evaluates this alert once a minute so changes are detected quickly. Because duration is used, Mini DBA can avoid treating a single short spike as a full incident when the condition clears quickly.
This alert helps detect memory pressure and cache efficiency problems. Low cache effectiveness or high memory pressure increases physical I/O, query latency, and the chance that a workload will become unstable during busy periods.
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: %. Major threshold: 90 %. Minor threshold: 95 %. Comparison direction: under. Duration is used, so prefer requiring the condition to persist before paging people for transient spikes. 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.
Check memory configuration, cache hit indicators, top memory consumers, and host pressure. Remove unnecessary competing services, tune query memory grants or work areas, adjust engine memory settings, and add RAM or resize the service tier when the working set has outgrown the instance.
If this alert is noisy, check whether the workload naturally has short bursts. Raise the duration or threshold for expected batch windows, but keep a lower route for production systems where user-facing latency matters. Avoid simply disabling the alert until you know whether the noise is caused by threshold choice or by a real capacity trend.