Disaster Recovery Sites: Hot, Warm, Cold and Cloud
Hot, warm, cold and cloud recovery sites compared. The BIA sets the RTO, and the RTO picks the site. A CISSP insight with a manager mindset.
TOPIC
Business Continuity
Planning for the day the system is gone: how long you can be down, how much data you can afford to lose, and where you fail over to. Impact analysis, recovery sites, and the metrics that all sit on one timeline. CISSP Domains 1 and 7.
Articles
RPO, RTO, WRT and MTD: Essential Disaster Recovery Metrics for CISSP
Master RPO, RTO, WRT and MTD for CISSP exam success: how the four disaster recovery metrics fit on one timeline, with worked examples and exam tips.
Key terms
The process that identifies critical business functions and the impact of their disruption over time, producing the recovery metrics (RTO, RPO, MTD) that drive continuity planning.
Alternate facility providing only space, power, and environmental support; hardware and data arrive after the disaster, so activation takes weeks, at the lowest standing cost.
Fully equipped alternate facility with hardware, software, and near-real-time data replication in place, able to take over within hours; the fastest and most expensive option.
The longest a business process can be unavailable before the damage becomes unacceptable. The outer boundary every other recovery metric must fit inside: RTO plus WRT.
The maximum data loss a business can tolerate, measured as a time window backwards from a disruption. RPO drives backup frequency: a one-hour RPO needs backups at least hourly.
The maximum time a business process can be down before recovery must complete. A CISSP Domain 7 metric: RTO plus WRT must fit inside the Maximum Tolerable Downtime (MTD).
Discussion-based walkthrough in which the response team talks through a disaster scenario against the plan, validating roles and decisions without touching any production system.
Alternate facility with hardware and connectivity in place but no current data; backups must be restored on activation, giving recovery in days at a fraction of hot-site cost.
The time after a system is technically restored spent verifying data, reconciling records, and resuming normal processing. RTO plus WRT must fit inside the MTD.