Imagine waking up one morning to find that your business applications are down completely.
The systems your company relies on are suddenly unavailable, leaving you scrambling to restore them.
How would you recover?
How quickly could you get back to business?
These are the very questions that every organization needs to ask itself when creating a disaster recovery (DR) plan.
The answer lies in a well-structured DR strategy that ensures your business operations don’t come to a standstill in the event of an unexpected outage.
One of the most effective ways to achieve this is by setting up a Pilot-Light Disaster Recovery Architecture in Oracle Cloud Infrastructure (OCI).
Let’s break this down and explore what pilot-light DR architecture is, how it works, and why it’s the go-to choice for businesses looking to stay resilient, even in the face of major disruptions.
What is a Pilot-Light DR Architecture?
First things first—what do we mean by pilot-light?
You might have heard the term in the context of gas-powered devices. A pilot light is a small, steady flame that’s always on. It doesn’t consume much fuel, but it can quickly fire up a larger device (like a heater) when needed.
Now, apply this idea to your business applications.
In the context of DR, a pilot-light environment refers to a minimal version of your business systems running at a remote location. It’s like having the core components of your workload—like essential configurations and important data—ready to go, even though they’re operating on a smaller scale.
When disaster strikes and the primary site is down, you can use these pre-configured resources to spin up a fully functional environment at a different location, bringing your business back online quickly.
This setup is designed to give businesses the perfect balance between cost and recovery speed. Instead of running an entire duplicate system (which can be expensive), the pilot-light approach runs only the critical components.
When needed, it allows businesses to scale up quickly, bringing a full-fledged environment back online in a matter of minutes.
The Components of a Pilot-Light DR Architecture in OCI
Setting up a Pilot-Light Disaster Recovery (DR) plan in Oracle Cloud Infrastructure (OCI) requires certain components to ensure everything is set up for a smooth failover process. Let’s take a look at the key elements that make up a pilot-light DR architecture:
- Regions: OCI offers different geographical regions. You’ll need to set up resources across at least two regions to ensure redundancy. If one region goes down, the other can take over.
- Availability Domains and Fault Domains: These are the building blocks of high availability in OCI. Availability domains are isolated locations within a region, and fault domains are physical data centers within those availability domains. Distributing your resources across different fault and availability domains ensures that a localized failure doesn’t take down your entire setup.
- Virtual Cloud Networks (VCN) & Subnets: These networks connect your various resources in OCI. Subnets help organize your cloud resources into specific security boundaries, ensuring that the right resources communicate securely with each other.
- Compute Instances: The heart of your workload. These virtual machines (VMs) are where your applications run. For pilot-light DR, you’ll only run the core, with minimal compute instances required to keep your application functional.
- Load Balancer: A load balancer is essential to ensure that traffic is directed to the right servers, even when failover occurs. It acts as the traffic director, sending users to the active region or server.
- Object Storage: This is where all your critical data resides. It’s highly available and durable, ensuring that your backups and data replication can happen seamlessly across regions.
- Block Volumes: OCI offers block volumes for storing data that requires frequent updates, like databases. These volumes can be replicated across regions to ensure that your data stays safe and can be restored quickly in case of an outage.
- Bastion Hosts: A bastion host is a server that acts as a gateway between your secure cloud environment and the outside world. It helps secure remote access to the infrastructure while ensuring the security of the network.
- NAT Gateway, Internet Gateway, and Service Gateway: These components handle different aspects of network connectivity, including private connections between your resources and internet access.
Building Your Pilot-Light DR Topology: The Basics
Now that we know the components, let’s take a look at how you can build a pilot-light DR topology that balances cost with performance.
- Choosing Your Regions and Availability Domains
- The first step is to choose two OCI regions for your disaster recovery setup. By selecting geographically separate regions, you ensure that your data is protected from localized failures. For example, if one region experiences a major outage, your other region can take over.
- Within these regions, you’ll deploy resources across multiple availability domains and fault domains. This guarantees that if one data center goes down, your applications are still available in another.
- Virtual Cloud Network Setup
- When you create each VCN, think about IP address requirements. Use a CIDR range (IP address range) large enough to accommodate all your resources and avoid any overlap with other networks.
- Design subnets based on the role and traffic flow of each resource. For example, place all the database resources in one subnet and the web servers in another for better isolation and security.
- Consider creating regional subnets for greater scalability and availability.
- Security Lists and Firewalls
- To enable smooth cross-region communication, especially for database replication or file storage, configure the necessary security lists. These will ensure that traffic can flow freely between your regions without running into firewalls or other security barriers.
- Backup Policies for Block Volumes
- Your block volumes (where your data resides) should be backed up regularly to meet your Recovery Point Objective (RPO). A good backup strategy ensures that if disaster strikes, you can restore your data to the most recent backup.
- Load Balancer Setup
- A load balancer ensures that even in the event of a disaster, traffic is directed to the right region or application. This helps maintain availability for your users even when the primary infrastructure is down.
Performance, Availability, and Cost Considerations
When planning your pilot-light DR strategy, there are a few key factors to keep in mind:
- Performance: When your systems failover to the backup region, the switch needs to be quick. This means planning for your RPO and Recovery Time Objective (RTO), ensuring that your systems can be restored to full capacity in the shortest time possible. Ensure that your volumes, backups, and compute instances are all optimized for fast recovery.
- Availability: You can ensure high availability through DNS steering, which directs user traffic to the active region after a failover occurs. This helps mitigate downtime.
- Cost: The pilot-light approach is cost-effective because it involves running only essential components of your workload at a minimal scale.
However, when a disaster occurs, your architecture must scale up quickly. You can automate this scaling using Terraform scripts, ensuring that you can quickly spin up additional resources in your secondary region.
Also, with NVMe devices and block volumes, you can optimize data backups and reduce costs.
Why Should You Choose Pilot-Light for Your DR Plan?
The pilot-light topology offers several benefits:
- Cost Efficiency: Instead of running duplicate systems at full scale, you only need the essential parts of your infrastructure running in a minimal state. This keeps your operational costs down while ensuring that you can quickly restore your business systems in the event of a disaster.
- Quick Recovery: Since the core elements of your workload are already set up, the failover process is fast. You don’t need to spend time setting up servers, databases, or storage from scratch.
- Scalability: Once the failover occurs, your system can scale up to meet the demands of a full recovery. This makes the pilot-light topology highly flexible and adaptable to changing business needs.
Conclusion
A well-planned Disaster Recovery (DR) strategy is essential for businesses that rely on their production applications. A pilot-light topology in Oracle Cloud Infrastructure provides an effective and cost-efficient way to ensure business continuity, even in the event of a disaster.
By setting up resources across multiple regions, using a scalable cloud infrastructure, and ensuring that your backup and failover processes are optimized, your business can recover quickly and efficiently.
And if you’re looking for expert assistance with OCI and building a solid DR strategy, connect with Tangenz, an Oracle Preferred Partner.
Our team can help you design, implement, and optimize your DR infrastructure, ensuring your business stays resilient no matter what.
