Explain Managed DB vs Self-Hosted.

Example

• A small SaaS team launching quickly uses AWS RDS to save time.
• Later, to cut costs and enable custom PostgreSQL extensions, they move to a Kubernetes-based self-hosted cluster.

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Why Is It Important

This decision affects:

• Uptime & reliability
• Developer velocity
• Operational cost
• Security & compliance Making the wrong call can increase on-call stress or inflate cloud bills.

Interview Tips

Frame your answer around:

• Workload patterns
• Ops skills/budget
• Compliance needs
• Migration and vendor lock-in Conclude with trade-offs and a reasoned recommendation.

Trade-offs

• Managed DB: +Fast setup, built-in backups, high availability; –Vendor lock-in, limited tuning, rising costs.
• Self-hosted: +Customization, portability, lower costs at scale; –Ops overhead, patching, slower delivery.

Pitfalls

• Assuming managed = infinite scale
• Ignoring hidden costs (egress, IOPS)
• Neglecting backup/restore testing
• Overlooking migration complexity
• Forgetting observability and capacity planning