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Design a backup and restore service

PremiumCloud infrastructureEasy

  • RPO and RTO
  • Incremental backups
  • Point in time recovery

Quick answer

This cloud infrastructure interview question asks you to design a backup and restore service. Aim for a design that runs reliably and securely in the cloud at a sensible cost, then explain the services, regions, deployment and trade-offs. Interviewers want to see how you balance reliability, security and cost.

The problem

Design a backup and restore service for a company's cloud: it takes scheduled backups of databases and disk volumes, keeps them safe from deletion and ransomware, and restores them quickly. The hard parts are meeting recovery point and recovery time targets, storing years of copies cheaply, and proving that restores actually work.

The recovery point objective (RPO) is how much recent data you may lose. The recovery time objective (RTO) is how long a restore may take.

What must a backup and restore service do?

  • Policies: Teams attach a policy to each resource: frequency, retention and copy rules. Tier 1 gets continuous log backup plus a daily snapshot; tier 2 gets a daily snapshot.
  • Backup jobs: A scheduler runs jobs on time; after the first full backup, later ones copy only changed data.
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How well must it do it?

  • RPO: At most 5 minutes for tier 1 and 24 hours for tier 2.
  • RTO: A 1 TB tier-1 database is serving again within 1 hour; tier 2 within 8 hours.
3 more requirementsUnlock to see all

What scale should you design for?

Use these numbers in your estimates.

The scale numbers unlock with this questionUnlock

Key concepts

  • RPO and RTO
  • Incremental backups
  • Point in time recovery
  • Immutable backups
  • Restore testing
  • Retention policies

How you’ll practise

6 short steps · save and come back any time
  1. Requirements
  2. Environments and topology
  3. Deployment pipeline
  4. Reliability and disaster recovery
  5. Observability and cost
  6. Wrap-up

Lala, personalized to you, gives a hint when you ask and reviews your design when you are ready.

What do interviewers look for?

In any cloud infrastructure design round.

  • Clarifies availability, security and cost targets
  • Chooses managed services with reasons
  • Plans regions, zones and failover
  • Covers identity, secrets and network boundaries
  • Explains deployment, rollback and observability
  • Keeps an eye on cost as usage grows

Questions people ask about this interview question

Which design type is this question?
It is a cloud infrastructure question. You design a backup and restore service and explain your choices the way you would in an interview.
Is this question asked at entry level?
It is marked Easy, so it suits engineers who are new to cloud infrastructure interviews. It is also a good warm-up before harder questions.
What should I cover first?
Start with the workloads, the availability target and the security and cost limits. Agree on scope with the interviewer before you design anything.
Can I practise it for free?
It is a premium question. Sign up and unlock it once for 10 credits; it then stays unlocked. When you finish, Lala, your personalized AI mentor, can review your design for 30 credits.

Related questions

Updated · Written by the SevyDevy team

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