Database Reliability 101: Backups, PITR, and Disaster Recovery Drills

Intro: Why Most Outages Turn into Data-Loss Incidents

A server crash isn't always catastrophic — data loss is. Many companies survive downtime but don't recover from corrupted or missing data.
Database reliability requires backups, point-in-time recovery, and disaster recovery planning — before disaster strikes.

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Backups Best Practices

1. Automate Backups

• Use daily full snapshots and hourly incremental backups.
• Test backup restore processes regularly.
• Store backups in at least two regions to avoid single points of failure.

2. Secure Backups

• Encrypt backups at rest and in transit.
• Use role-based access control (RBAC) for backup credentials.
• Rotate encryption keys regularly.

Example: Automate Postgres Backups with pg_dump

pg_dump -U myuser -h mydb.example.com mydb | gzip > mydb-$(date +%F).sql.gz

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Point-in-Time Recovery (PITR) for Postgres/MySQL

PITR lets you restore a database to any point before data corruption or accidental deletes.

Postgres PITR Example:

1. Enable WAL (Write Ahead Log) archiving.
2. Store WAL segments in durable storage (e.g., S3).
3. Restore base backup + replay WAL files up to the target timestamp.

pg_basebackup -D /data/backup -Fp -Xs -P -U repl
pg_waldump /data/backup/wal | grep "target-timestamp"

MySQL PITR Example:

• Use binary logs for incremental recovery.
• Combine the latest full backup + replay binlogs to the exact point.

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Disaster Recovery (DR) Planning

1. Define RPO and RTO

Knowing these numbers lets you choose the right backup frequency and failover architecture.

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2. Design Cross-Region DR Strategies

• Maintain replicas in multiple regions for redundancy.
• Use managed database services (Aurora, Cloud SQL, AlloyDB) for simplified cross-region failover.
• Regularly test restoring backups in another region.

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Chaos Drills for Database Resilience

Running planned failure simulations ensures you can recover when things break.

Chaos Drill Examples:

• Kill the primary database instance.
• Trigger a replica promotion and measure time to recovery.
• Simulate network partitions between app and DB.

Goal: Compare measured failover time vs defined RTO.

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Case Study: Restoring a Corrupted Production Database Without Losing Data

Scenario:
A SaaS company running Postgres had a bad migration that corrupted customer data.

Actions Taken:

• Triggered PITR to restore database up to 2 minutes before corruption.
• Validated recovered data integrity using nightly checksums.
• Switched traffic to the restored replica without downtime.

Outcome:
Zero customer data loss, full recovery in under 12 minutes. Confidence in their DR plan improved drastically.

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Database HA + PITR + Cross-Region DR Flow

Key Takeaways

• Automate full + incremental backups and test restores often.
• Use PITR to recover from corruption or accidental data loss.
• Define clear RPO and RTO to guide reliability goals.
• Build cross-region DR strategies for multi-region resilience.
• Run chaos drills to validate your failover readiness.

Database reliability is less about avoiding outages and more about recovering safely when they happen.