Azure SQL Database data file write time alert


The Data File Write Time alert notifies you when its configured condition is met on Azure SQL Database instances so you can investigate and respond.

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Alert summary

  • Platform: Azure SQL Database
  • Alert category: Disk
  • Default enabled: true
  • Default evaluation frequency: Minute
  • Threshold label: Milliseconds
  • Unit: Ms

What Mini DBA checks

This alert measures point-in-time data-file write latency in milliseconds. Use it to find short periods of unusually slow storage that an average-latency alert may hide. Mini DBA evaluates the condition once a minute so changes are detected quickly.

How this alert helps

This alert helps identify storage latency that can slow transactions and database work even when longer-term averages still look acceptable.

When to enable it

Enable it on any monitored Azure SQL Database instance where this condition would require an administrator to investigate or communicate with the application team. Tune noisy development systems after you have a short baseline.

Threshold guidance

The default minor threshold is 1,500 ms and the major threshold is 10,000 ms. Compare these values with the database's normal write latency and require the condition to persist long enough to avoid paging on an isolated storage spike.

Remediation for an active alert

Identify the affected data file and time window, then compare write latency with query load, waits, service-tier utilisation, maintenance, and recent growth. Reduce avoidable I/O or increase storage/service capacity when the workload has genuinely exceeded it.

Investigation workflow

  1. Confirm the alert is still active and note the first seen time, affected instance, and severity.
  2. Review the affected data file, recent latency trend, query workload, waits, and service-tier resource use.
  3. Compare the current value with the normal baseline for the same time of day or maintenance window.
  4. Record the cause, corrective action, and whether thresholds or routing should be adjusted after the incident.

Avoiding alert noise

If the alert creates repeated noise, review whether it is enabled on the correct instances, whether maintenance windows are configured, and whether the minor and major routes match the real business impact. Keep enough history to prove the new setting before changing it broadly.

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