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Disaster recovery RTO/RPO definition and practice

An operation guide that increases DR reliability by not only completing backups but also including recovery rehearsals

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Disaster RecoveryBackupSREOperations

Introduction

DR strategy may seem like a cost in peacetime, but it becomes a survival condition in moments of failure. Many organizations fail to achieve their goals because they only set RTO/RPO in numbers and do not verify actual recovery procedures. This article explains practical methods for defining RTO/RPO appropriate for service characteristics and designing practice cycles.

재해복구 RTO/RPO 정의와 연습 커버
Wikimedia Commons 기반 무료 이미지

Problem definition

The cause of disaster recovery failure is missing assumptions rather than technology.

  • The same goal is enforced by not distinguishing between core and non-core services.
  • Backups exist, but there is no restoration verification, so the actual recovery time cannot be predicted.
  • The order of DNS, secret, and batch jobs during DR conversion is not documented.

RTO/RPO is a sequence, not an SLA phrase. It makes sense to have a playbook that includes recovery sequences and decision makers.

Key concepts

perspectiveDesign criteriaVerification points
CategorySeparation of goals by service tierTier1 goal achievement rate
data protectionSnapshot + WAL + OffsiteRestoration point error
Transition ProcedureNetwork/Application/Deployment SequenceTotal recovery time
trainingQuarterly DR DrillError compared to actual

The most effective improvement is drill automation. Recovery commands and verification reports must be created as scripts to perform repeatable exercises.

Code example 1: Recovery check script

#!/usr/bin/env bash
set -euo pipefail

./scripts/dr/restore-db.sh --target-time "$1"
./scripts/dr/restore-object-storage.sh
./scripts/dr/switch-dns.sh --to standby
./scripts/dr/health-check.sh --region standby

printf "DR drill completed at %s\n" "$(date -Iseconds)"

Code example 2: RTO/RPO goal declaration

services:
  checkout:
    tier: 1
    rto_minutes: 30
    rpo_minutes: 5
  blog:
    tier: 2
    rto_minutes: 120
    rpo_minutes: 30
  analytics:
    tier: 3
    rto_minutes: 360
    rpo_minutes: 120

Architecture flow

Mermaid diagram rendering...

Tradeoffs

  • If RTO/RPO is set aggressively, the cost of infrastructure redundancy increases significantly.
  • Automated DR is fast, but risky without script self-verification.
  • Increasing the frequency of drills increases readiness, but increases the cost of operating team time.

Cleanup

DR is completed through repeated practice, not documentation. By clearly dividing goals by tier and automating the recovery process, predictable recovery times can be achieved even in real-world failures.

Image source

  • Cover: source link
  • License: AGPL / Author: Proxmox Server Solutions GmbH
  • Note: After downloading the free license image from Wikimedia Commons, it was optimized to JPG at 1600px.

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