Certified Information Security Manager (CISM)Incident ManagementMedium
A global manufacturing company relies heavily on its Enterprise Resource Planning (ERP) system for daily operations. A recent business impact analysis (BIA) determined that the maximum tolerable downtime (MTD) for the ERP system is 4 hours. Which of the following recovery strategies would BEST support meeting this MTD, assuming a significant system failure?
- AA warm site with daily incremental backups and manual restoration.
- BCloud-based archival of historical data with an on-demand recovery environment.
- CA hot site with real-time data replication and automated failover.
- DDaily full backups to tape, stored offsite with weekly retrieval.
Show answer & explanationAnswer & explanation
Correct answer: C. A hot site with real-time data replication and automated failover.
An MTD of 4 hours is extremely aggressive, indicating a need for near-instantaneous recovery. A hot site with real-time data replication and automated failover provides the fastest recovery time, typically measured in minutes or very low hours, making it the best option to meet such a strict MTD for a critical system.
Why the other options are wrong
- A. A warm site requires significant setup and data loading, meaning RTOs would likely be 12-72 hours, exceeding the 4-hour MTD.
- B. On-demand recovery environments still require provisioning and data loading, making a 4-hour MTD challenging, especially for a complex ERP system.
- D. Tape backups with weekly retrieval would result in RTOs (Recovery Time Objectives) far exceeding 4 hours due to transport and restoration time.
Maximum Tolerable Downtime (MTD)
The absolute maximum period of time an organization can tolerate for a system or business function to be unavailable after a disaster or incident.
- Determined by Business Impact Analysis (BIA).
- Drives RTO and RPO requirements.
- Critical for selecting appropriate recovery strategies.
Memory trick: Hot, Warm, Cold: Speed costs money. Cold is cheap, Hot is fast.