Distinguish Azure metric retention from the maximum chart time range

Source facts

Microsoft distinguishes 93-day retention for platform and custom metrics from the 30-day maximum time span for one Metrics-tile chart. It advises checking the selected start and end dates when a chart is blank or incomplete. The stated chart restriction does not apply to log-based metrics. Microsoft Learn.

Applicability

Use this review for platform or custom metrics viewed in the Metrics tile. Identify the metric category and requested interval before drawing conclusions about historical availability. Keep this guidance separate from Prometheus retention, log-based metrics and any configured external export destination.

DSE recommendation

DSE recommends recording the requested period and then inspecting it in supported chart intervals. Preserve the metric name, resource and aggregation while moving across the historical window. Ask the reporting owner to distinguish unavailable measurements from a display-range limitation in the final report. Avoid changing retention settings solely because one overlong chart appears empty.

Verification

Select a supported interval containing known historical measurements and confirm that the chart renders. Move the interval to cover the remainder of the period being investigated and record any actual gaps. Compare those gaps with independent collection evidence where available. Retain the time-picker settings so a reviewer can reproduce the history check rather than relying on an unlabeled screenshot.

Official references

Microsoft Learn: Metrics in Azure Monitor.