As organizations increasingly adopt cloud services, having a disaster recovery plan for those cloud workloads becomes critical. There are several options for protecting cloud-based infrastructure and data in the event of an outage or disaster. In this article, I will provide an in-depth look at the various cloud disaster recovery approaches available.
Backup and Restore
One of the most basic disaster recovery methods is to regularly back up your cloud data and infrastructure, then restore from those backups in the event of a disaster.
Pros
- Relatively simple to implement
- Leverages native backup tools provided by cloud platforms like AWS Backup, Azure Backup, and Google Cloud Backup and Restore
Cons
- Lengthy recovery time objectives (RTOs)
- Potential data loss between last backup and when disaster struck
- Manual process to spin up resources from backups
Backup and restore works best for non-critical workloads that can tolerate some downtime and potential data loss.
Pilot Light
The pilot light approach keeps a minimal version of an application always running in the cloud. When a disaster strikes, the pilot light instance can be quickly scaled up to restore service.
Pros
- Faster recovery time than full backup/restore
- Near-zero RTO
- Lower cost to maintain pilot light vs. full production environment
Cons
- Some data loss since production data is not fully replicated
- Manual intervention required to redirect traffic and scale up pilot light resources
Pilot light is a good option for core applications that need faster recovery but don’t require zero RTO or data loss.
Warm Standby
A warm standby keeps a full copy of your production environment and data always running in the cloud. This provides a ready-to-go backup site if the primary production environment becomes unavailable.
Pros
- Very fast RTO – redirect traffic and recover almost instantly
- No data loss
- Automated failover possible
Cons
- More expensive to run full production environment at all times
- Some manual intervention may still be required
Warm standby is ideally suited for mission-critical applications that justify a higher cost for very low RTO and near-zero data loss.
Multi-Region Deployments
With a multi-region deployment, an application is actively running in at least two separate geographic cloud regions. If one region becomes unavailable, traffic can be redirected to the alternate region.
Pros
- Very fast recovery if managed by DNS redirect or a global load balancer
- No data loss
- Works for entire application environment and data
Cons
- Most expensive option – pay for two full production environments
- Some latency increase for normal operations
- Complex application architecture required
This option is best for extremely high-availability applications that justify the costs of an active-active site.
Orchestration and Automation
Automation and infrastructure-as-code techniques help minimize downtime by allowing damaged cloud resources to be quickly recreated after a disaster.
Pros
- Faster recovery times by automatically spinning up resources quickly
- Flexibility to recreate environment according to latest configs
- Cost-effective way to add resiliency
Cons
- Some manual intervention still required
- Potential for data loss depending on backup schemes
- Script maintenance overhead
Automation works well alongside the other options to handle faster recovery of resources and minimize human effort.
Choosing the Best Cloud DR Approach
When selecting a cloud disaster recovery approach, key factors to consider include:
- Recovery time objective (RTO) – How fast must services be restored to avoid unacceptable impacts?
- Recovery point objective (RPO) – How much potential data loss can be tolerated?
- Cost – How much are you willing to pay for greater availability and data protection?
- Complexity – How much configuration effort can be sustained to enable DR capabilities?
The best disaster recovery solution likely combines multiple methods like backup, replication, redundancy, and automation. With proper planning and testing, organizations can now design resilient cloud architectures to minimize disruption in the event of a disaster.
