BeginnerScenario
5 min
HTTP 503 Errors During DB Maintenance
DatabasesMaintenanceAvailability
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Interview Question
Users face 503 errors during scheduled DB maintenance. How do you minimize impact and handle gracefully?
Key Points to Cover
- Announce and schedule during low-traffic windows
- Failover to replicas or use read-only mode
- Use connection draining and retries in app
- Show user-friendly error or maintenance page
- Add automation to shorten maintenance window
Evaluation Rubric
Plans maintenance with low impact30% weight
Mentions replicas or failover30% weight
Provides graceful user handling20% weight
Automates/reduces downtime20% weight
Hints
- 💡Maintenance windows should have rollback plans.
Common Pitfalls to Avoid
- ⚠️Performing maintenance during peak hours without prior notice.
- ⚠️Not having a clear communication plan for users.
- ⚠️Assuming read replicas are always sufficient without verifying read/write traffic patterns.
- ⚠️Implementing aggressive retries without backoff, leading to system overload.
- ⚠️Lack of a tested rollback plan, causing extended downtime when issues arise.
Potential Follow-up Questions
- ❓How to make DB upgrades zero-downtime?
- ❓What about schema migrations?
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