The first step in building a disaster recovery plan (DRP) for critical on-prem applications is to determine what is actually “critical” to the business, how long the organization can tolerate those applications being down, and therefore what restoration order (prioritization) is required. That prioritization must come from business/data owners and stakeholders, because they understand operational dependencies, business impact, and acceptable downtime.

This is essentially the start of a Business Impact Analysis (BIA) and related continuity prioritization work, which precedes choices like vendors, contracts, or site geography. You don’t select a DR site/vendor or negotiate agreements until you know which systems must be restored first and what recovery objectives you must meet.

Supporting exact extracts:

The All-in-One CS0-003 guide explains that the foundation is identifying critical systems and determining tolerable outage time (used to prioritize restoration):Exact extract (All-in-One Exam Guide): “The key is to determine which of the organization’s critical systems are needed for survival and then estimate the outage time that can be tolerated by the organization…” It then connects those determinations directly to prioritization:Exact extract (All-in-One Exam Guide): “These estimates will help you determine how to prioritize response team efforts to restore these assets.”

The Secbay Press CS0-003 guide lays out the early BIA/risk identification steps in order, starting with identifying what’s critical before recovery priorities:Exact extract (Secbay Press): “1. Identify critical processes and resources2. Identify outage impacts and estimate downtime3. Identify resource requirements4. Identify recovery priorities”

Why the other options are not the first step:

A / C (vendor selection / vendor agreements): those come after requirements are defined (RTO/MTD, criticality, order of restoration).

D (define geographic area): location considerations are important, but they are driven by requirements and constraints discovered during BIA/continuity prioritization (what needs to be recovered, how fast, and with what dependencies).

References (CompTIA CySA+ CS0-003 documents / study guides used):

Mya Heath et al., CompTIA CySA+ All-in-One Exam Guide (CS0-003): determine critical systems and tolerable outage time; used to prioritize restoration

Secbay Press, CompTIA CySA+ Exam Prep Guide (CS0-003): BIA / risk identification process steps (identify critical processes/resources → estimate downtime → recovery priorities)