How do you backup, restore, and migrate websites safely?

Long Answer

A disciplined approach to backups, restores, and migrations ensures websites remain resilient, even under failure or high-traffic changes. The strategy blends automation, encryption, version control, and staging to protect both data and uptime.

1) Backup strategies
A reliable system backs up both site files (themes, plugins, uploads, configs) and databases (content, users, transactions). I implement:

• Automated backups scheduled daily or hourly depending on SLA.
  
• Incremental backups for efficiency, storing only changed data.
  
• Offsite storage via cloud buckets (S3, GCS, Azure Blob) with lifecycle rules.
  
• Encryption at rest and in transit, using KMS for keys.
  
• Retention policies, e.g., 7 daily, 4 weekly, 12 monthly backups.
  

2) Restore workflows
A backup is worthless unless verified. I enforce restore testing on staging servers at least quarterly. Integrity is validated with checksums and post-restore smoke tests (login, checkout, forms). Restore procedures include:

• Granular restores for single files/tables (e.g., corrupted wp_options row).
  
• Full restores when systems crash.
  
• Disaster recovery plans, documented with RTO/RPO goals.
  

3) Migration planning
Website migrations—whether between hosts, platforms, or domains—are high-risk. I mitigate risks via:

• Staging dry runs: replicate the target infra, replay migration steps, and record timings.
  
• Database sync tools like mysqldump, pg_dump, rsync, or CMS-specific plugins for schema/content transfer.
  
• Blue-green deployments: cut over traffic only once new infra is fully validated.
  
• DNS strategy: lower TTLs in advance to enable fast rollback or switch.
  
• Zero-downtime practices: content freeze during final sync, queueing writes, or read-replicas.
  

4) Version control for code and configs
All code and configuration lives in Git repositories. Infrastructure as Code (Terraform/Ansible/Docker Compose) ensures the environment is reproducible. Secrets stay in secret managers, not repos. Release pipelines validate builds and rollback automatically if errors spike.

5) Data consistency and integrity checks
After backup or migration, I verify checksums, table counts, and file diffs. Application-level tests confirm no broken media, orphaned records, or missing dependencies. Monitoring ensures database queries, cache, and API endpoints perform as expected.

6) Automation and monitoring
Backups integrate with CI/CD pipelines. Logs and alerts notify if a backup fails or deviates in size. Observability dashboards track job durations, success rates, and restore drills. For migrations, logs are centralized and reviewed before and after DNS cutover.

7) Security and compliance
Compliance frameworks (GDPR, SOC2, HIPAA) require encrypted backups, controlled retention, and secure deletion. Audit logs capture who initiated restores or migrations. Role-based access control ensures only trusted admins handle sensitive data.

8) Real-world example
For an eCommerce migration, I ran incremental DB syncs nightly until cutover day, locked carts during final sync, and flipped DNS with a 5-minute TTL. Restores were tested three times before launch. Post-migration monitoring confirmed no data loss, with orders replayed via logs for full integrity.

By layering automation, staging drills, and integrity validation, I ensure backups and migrations don’t just exist on paper—they work under stress and safeguard both data and business continuity.

‍

Table

‍

Common Mistakes

Frequent pitfalls include relying on manual backups or storing them on the same server—leading to total loss in case of compromise. Teams often skip restore testing, discovering corrupted backups only after disasters. Migrating live databases without a content freeze risks lost writes or double orders. Developers sometimes forget to lower DNS TTLs, making rollbacks slow. Another mistake is failing to encrypt backups, exposing sensitive data if leaks occur. Ignoring version control for configs creates drift between environments. Finally, neglecting monitoring means unnoticed failed backups or silent data corruption, which surfaces only when users complain.

‍

Sample Answers (Junior / Mid / Senior)

Junior:
“I use plugins or host tools for daily backups. I save files and databases to cloud storage. For restores, I test on staging, then apply live. During migrations, I copy files and DB, then update configs and DNS.”

Mid:
“I automate incremental + full backups with offsite encrypted storage. Restores are tested quarterly on staging. For migrations, I run dry runs, sync DB with tools like rsync + mysqldump, and lower DNS TTL. I keep configs in Git to ensure reproducibility.”

Senior:
“I design policies: automated offsite backups (retention tiers, KMS encryption), quarterly restore drills, and monitoring for anomalies. Migrations follow blue-green with cutover via DNS, database syncs, and rollback plans. Infrastructure is codified in Git/Terraform for consistent restores. Data integrity is validated with checksums and diff tools, while dashboards show backup health and migration logs. Compliance (GDPR/SOC2) is ensured via audit trails.”

‍

Evaluation Criteria

Interviewers expect candidates to:

• Describe layered backup strategies (incremental, offsite, encrypted).
  
• Stress the importance of restore drills and checksum verification.
  
• Demonstrate migration planning: staging, dry runs, DNS TTLs, blue-green cutovers, rollback procedures.
  
• Explain how Git + IaC enforce reproducible infrastructure/configs.
  
• Address data integrity (checksums, diffs, smoke tests).
  
• Mention monitoring of backup health and migration logs.
  
• Cover security & compliance: encryption, RBAC, audit logs.
  Weak answers only mention “I take backups” without testing or planning. Strong answers tie automation, restore verification, and risk mitigation into a unified operational process.
  
  

Preparation Tips

Set up a lab project:

1. Automate daily backups of code and DB to cloud storage (S3 + lifecycle rules).
   
2. Encrypt backups with KMS keys.
   
3. Run a restore on a staging server monthly; verify with checksums and smoke tests.
   
4. Practice migrations: spin up a clone of production, sync DB with mysqldump/pg_dump, update configs, and test before DNS cutover.
   
5. Codify infra with Terraform/Ansible so environments are reproducible.
   
6. Lower DNS TTL and rehearse rollback.
   
7. Track metrics: backup size, job duration, error logs.
   
8. Document playbooks: RPO/RTO targets, who to alert, rollback checklist.
   Finally, prepare a 60–90s story about a migration or restore drill, highlighting the risks avoided through planning and validation.
   
   

Real-world Context

A SaaS provider running multiple WordPress + Django apps needed safe migrations to a new cloud host. We automated incremental backups to S3, encrypted with KMS, and stored 90-day retention tiers. Before migration, we staged full dry runs: syncing DB snapshots nightly, running diff tools, and testing restores on cloned VMs. On cutover day, DNS TTL was dropped to 300s, content was frozen for 15 minutes, and final sync completed. Blue-green ensured old infra remained intact until validation passed. Monitoring dashboards tracked restore times and error rates; alerts fired if discrepancies arose. Post-migration, checksum diffs confirmed zero corruption, and business KPIs (orders, logins) validated integrity. Result: migration completed with <10 minutes downtime, no data loss, and fully auditable recovery plans—building long-term client trust.

‍

Key Takeaways

• Automate backups: files + DB, incremental + offsite, encrypted.
  
• Test restores on staging; use checksums and smoke tests.
  
• Plan migrations with staging dry runs, blue-green, DNS TTL cuts.
  
• Version control configs + infra with Git/Terraform.
  
• Monitor backup jobs, integrity, and restore times.
  
• Bake in compliance: encryption, RBAC, audit logs.
  
  

Practice Exercise

Scenario: You’re tasked with migrating a high-traffic eCommerce website from on-prem to AWS with minimal downtime.

Tasks:

1. Automate file + DB backups with hourly incrementals and daily fulls to S3. Encrypt with KMS and apply lifecycle retention.
   
2. Test restores weekly on staging; run checksum comparisons and smoke tests (checkout, login).
   
3. Stage a dry run migration: replicate infra in AWS, import DB snapshot, rsync media, and validate performance.
   
4. Lower DNS TTL to 300s two days before cutover.
   
5. On migration day: freeze content, take final snapshot, sync to AWS, and validate.
   
6. Apply blue-green cutover: switch DNS only after validation passes; keep old infra intact for rollback.
   
7. Post-migration: run reconciliation (file diff, DB row counts), restore scripts, and monitoring.
   
8. Document RTO/RPO results and share with stakeholders.
   
   

Deliverable: Provide a 2-minute walkthrough of how your process ensures backups are reliable, restores are proven, and migration can occur with zero data loss and minimal downtime.