Data Monitoring / MySQL Monitoring
MySQL: Binary log retention headroom
A disconnected replica risks losing required source history. Compare its recovery position with source binary log retention and expected outage duration.
Environment and inputs: MySQL 8.4 baseline; Performance Schema consumers, privileges and replication topology affect evidence availability.
Failure scenario
A disconnected replica risks losing required source history. Confirm the cause before choosing a fix.
Evidence to collect
Compare its recovery position with source binary log retention and expected outage duration. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Restore progress or extend a justified retention window while monitoring source disk capacity. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for binary log retention headroom using the same scope and a representative interval. Check that the symptom is resolved, expected records are present and downstream results are correct. If coverage, correctness or latency worsens, restore the recorded configuration through the agreed rollback process.
Scope and precautions
Prefer read-only access and limit queries to the relevant period or dataset. This example has not been tested on your systems. Test changes in an approved environment. Keep credentials and sensitive data out of shared evidence.