A cyberattack, a major hardware failure, a server room fire, or a critical human error are no longer hypothetical risks, but statistical certainties. Faced with the sudden shutdown of the information system, a company's survival depends not on its ability to avoid the disaster, but on its speed in overcoming it. This is where the Business Continuity Plan (BCP) comes in.
PRA vs PCA: What's the Difference?
Business Continuity Plan (BCP) and Business Recovery Plan (BRP) are often confused.
- The BCP (Business Continuity): Aims to maintain the company's activity during the crisis (e.g., switching to manual processes, forced teleworking).
- The Disaster Recovery Plan (DRP): Focuses strictly on the technological infrastructure. It defines the technical procedures for rebuilding and restarting the information system (servers, networks, data) after a total crash.
The Two Fundamental Pillars: RTO and RPO
The design of a Disaster Recovery Plan (DRP) is based on two crucial metrics, defined in agreement with senior management and the various business units:
| Metric | Meaning | Key question to ask yourself | Example of a target |
|---|---|---|---|
| RPO (Recovery Point Objective) | Maximum permissible data loss. | "How many hours or days of work can we accept losing and having to redo?" | 4 hours (requires very frequent backups). |
| RTO (Recovery Time Objective) | Maximum allowable interruption time. | "How long can we survive without our servers and applications?" | 12 hours (requires a rapid backup infrastructure). |
Strategic tip: The closer RTO and RPO get to zero, the more infrastructure costs (synchronous replication, high availability) skyrocket. The whole point of disaster recovery planning is to find the balance between the cost of the solution and the cost of production downtime.
The 4 Steps to Building an Infallible Disaster Recovery Plan
1. Business Impact Assessment (BIA)
Before purchasing any technical solution, it's essential to audit the existing system. Business Intelligence (BIA) allows you to map business processes and identify critical assets.
- Tier 1 (Critical): ERP, customer databases, messaging (RTO < 4h).
- Tier 2 (Important): Internal file servers, intranet (RTO < 24h).
- Tier 3 (Non-critical): Archives, test servers (RTO > 48h).
2. Choosing a Relief Strategy
Depending on the budget and criticality, the company must choose the type of backup infrastructure:
| Site Type | Description | Advantages / Disadvantages |
|---|---|---|
| Cold Site | Premises equipped with electricity/network, but without pre-installed equipment. | Inexpensive, but very long RTO (several days). |
| Warm Site | Hardware is present, but the data needs to be restored from backups. | Good cost/performance compromise (RTO of 12h to 48h). |
| Hot Site | Real-time replication of production. Exact mirror. | RTO is virtually zero, but extremely expensive. |
| DRaaS (Cloud) | Disaster Recovery as a Service. Switchover to public/private cloud in case of crash. | Flexible, scalable, transforms CAPEX into OPEX. |
3. Drafting Technical Procedures
A Business Continuity Plan (BCP) is not a vague guideline; it is a step-by-step emergency manual. It must contain:
- The decision tree: who has the authority to trigger the PRA?
- The contact details of the crisis unit (internal staff, service providers, insurance companies).
- The strict order of system restarts (e.g., the domain controller, the network, then the databases, and finally the web servers).
- Network reconfiguration procedures (DNS, IP redirections, VPN).
4. Testing and Operational Maintenance (MCO)
A disaster recovery plan (DRP) that hasn't been tested doesn't exist. The technological environment evolves every week (new servers, updates, new networks).
- Perform a mock test (Tabletop exercise) every 6 months.
- Perform a real technical failover test at least once a year over a weekend.
Deploying a robust Disaster Recovery Plan (DRP) is now a legal and regulatory requirement, particularly with the entry into force of the European NIS2 directive, which mandates concrete cyber-resilience measures. At Onetosecure, we support companies in auditing their infrastructures, defining Business Impact Assessments (BIAs), and technically deploying business continuity solutions, so that even the worst-case scenario becomes a manageable process.