Recovery time objective (RTO) and recovery point objective (RPO) are two important metrics used to measure the effectiveness of a business continuity and disaster recovery strategy. While they sound similar, RTO and RPO measure different aspects of the recovery process. Understanding the differences between RTO and RPO is critical for organizations that want to build resilient IT operations.
What is Recovery Time Objective (RTO)?
The recovery time objective refers to the maximum acceptable length of time that a business process or service can be disrupted after a disaster. RTO represents the time it takes to recover from a disruption and resume normal operations. It is typically measured in hours or minutes.
RTO considers how long it will take to restore a business process or service after a disruption occurs. For example, an organization may set an RTO of 4 hours for restoring email services after an outage. This means the business aims to have email back up and running within 4 hours after a disruption.
Some key things to know about RTO:
- Focuses on how long it takes to recover and resume operations after a disruption
- Measures the maximum acceptable downtime
- Specified in hours and minutes (e.g. 1 hour RTO, 4 hour RTO)
- Defined on a per-system or application basis
- Indicates the recovery priorities for systems – lower RTOs indicate higher priority
RTO does not account for data loss. It is concerned with restoring service availability and performance, not data. RTOs are agreed upon based on business requirements and impact analysis.
What is Recovery Point Objective (RPO)?
The recovery point objective refers to the maximum acceptable amount of data loss measured in time. RPO represents how much data can be lost before it significantly impacts the business.
RPO measures the point of data recovery, not service recovery. It indicates how far back in time you need to recover data to before the disruption occurred. For example, a company may establish an RPO of 1 hour. This means they must be able to recover data to a point within the last hour.
Some key things to know about RPO:
- Focuses on how much data loss is acceptable
- Measures amount of data loss in a time window (e.g. 1 hour RPO)
- Indicates how often backups need to occur
- Defined on a per-system or application basis
- Lower RPOs require more frequent backups and tighter SLAs
RPO measures the amount of acceptable data loss, not service disruption. RPOs are set based on data criticality and tolerance for data loss.
Key Differences Between RTO and RPO
While RTO and RPO sound similar, they measure distinct aspects of recovery:
- RTO – How long until a system recovers and is operational
- RPO – How much data can be lost until recovery
Here are some key differences between RTO and RPO:
| RTO | RPO |
|---|---|
| Measures duration of service disruption | Measures data loss |
| Indicates how quickly service must be restored | Indicates how often backups should occur |
| Specified in hours and minutes | Specified in time units (e.g. minutes, hours) |
| Focus is on service and performance | Focus is on data loss |
RTO and RPO complement each other in determining recovery priorities. Tight RTOs generally require tighter RPOs so less data is lost when recovering quickly. Longer RTOs allow for higher RPOs.
Setting Appropriate RTOs and RPOs
Recommended RTOs and RPOs vary significantly across different systems, applications and data types. There are no universally ideal numbers. RTOs and RPOs should be set based on:
- Business requirements – How much downtime and data loss can business processes tolerate?
- Recovery costs – Tighter RTOs and RPOs require more investments in resilience.
- Data criticality – More critical data requires tighter RPOs.
- Compliance – Regulatory and data privacy standards may dictate RTO/RPO limits.
As a general guideline, most organizations target RTOs between 0-24 hours and RPOs from 0-24 hours. But acceptable RTOs and RPOs can vary significantly based on data criticality and recovery costs.
Transactional, customer-facing systems often have tighter RTOs and RPOs. Batch processing systems and archives may have longer RTOs and RPOs.
Sample RTOs and RPOs by System
| System | RTO | RPO |
|---|---|---|
| CRM system | 1-2 hours | 15-30 minutes |
| Email system | 0-1 hours | 15-30 minutes |
| Payroll system | 2-4 hours | 1-2 hours |
| Supply chain management | 6-12 hours | 2-4 hours |
| Data warehouse | 24 hours | 6-12 hours |
Measuring and Reporting on RTOs and RPOs
Once RTOs and RPOs are established, they should be measured and monitored over time. This involves tracking:
- Actual recovery times (ART) – The actual duration of disruptions and outages.
- Actual data loss – The actual amount of data lost in events.
This performance data should be continually reported and compared to RTO and RPO targets. If actual recovery times and data loss exceed the agreed upon objectives, it signals a gap in capabilities.
RTOs and RPOs that are frequently missed indicate a need for greater investment in resilience such as more redundancy, backup capacity, and disaster recovery testing. By measuring ART and data loss, organizations can validate recovery plans and pinpoint high risk areas.
Using RTOs and RPOs for Disaster Recovery Planning
RTOs directly influence disaster recovery strategies. Short RTOs typically require automated disaster recovery with active redundancy:
- High availability/clustering – Servers are clustered so if one fails, its load is automatically picked up by another node.
- Hot failover sites – Critical systems failover to a mirror backup site that is continually synchronized.
- Active-active data centers – Workloads run simultaneously in multiple data centers.
Longer RTOs allow for recovery using backups and passive redundancy:
- Cold failover sites – Backup facilities are powered off until a disaster is declared.
- Warm standby sites – Backup facilities are powered on but not running production workloads.
- Backup restores – Services are recovered from backup media.
RPOs influence the backup strategy. Short RPOs require more frequent backups and database transaction logs:
- Incremental backups – Back up only data changed since last backup.
- Snapshots – Frequent point-in-time copies of production data.
- Mirroring – Real-time data replication to failover site.
Higher RPOs allow for less frequent backup schedules:
- Full daily backups
- Weekly full backups with daily incrementals
- Asynchronous data replication
By aligning disaster recovery plans with RTO and RPO targets, organizations can achieve the right balance of risk mitigation and cost.
Conclusion
Recovery time objective and recovery point objective provide measurable targets for service recovery and data loss in disaster scenarios. While closely related, RTO measures how quickly systems and data must be restored, while RPO defines limits on data loss. RTOs and RPOs should be set based on business needs, data criticality, and regulatory requirements. Organizations can then design disaster recovery strategies, backup policies, and failover architecture to meet these objectives.
By implementing resilient IT infrastructure aligned to RTO and RPO targets, businesses can quantitatively improve their ability to withstand disruptions. Tracking actual recovery times and data loss against the objectives highlights gaps to be addressed. RTO and RPO provide a strategic framework for balancing recovery agility with cost.
