hardMultiple ChoiceObjective-mapped
Insufficient Replication Bandwidth: Upgrading to Meet RPO
An online retail company runs its e-commerce platform on a virtualized infrastructure with 50 virtual servers. The platform experiences intermittent slowdowns during peak hours, and recent monitoring reports show that disk I/O latency on the storage area network (SAN) frequently exceeds 50 ms during these periods. The SAN has two fabric switches and a single storage array with 12 TB of usable capacity, currently at 80% utilization. The company’s disaster recovery plan requires recovery point objective (RPO) of 1 hour and recovery time objective (RTO) of 4 hours for the e-commerce platform. During a recent test failover to the disaster recovery site, the IT team discovered that the replication link between primary and DR sites is saturated, causing replication lag of up to 3 hours. The team also noted that the DR site storage has only 6 TB of usable capacity, now at 60% utilization. The IT manager is concerned about meeting the RPO and RTO. Which course of action should the IT team take first?
Quick Answer
The correct first step is to upgrade the replication link between primary and DR sites to a higher bandwidth connection, because the saturated link directly causes the 3-hour replication lag that violates the 1-hour RPO. In disaster recovery architecture, insufficient replication bandwidth creates a bottleneck where data changes cannot be transmitted quickly enough to meet the required recovery point objective, regardless of other infrastructure improvements. On the CISA exam, this scenario tests your ability to prioritize the root cause of an RPO failure—a common trap is to focus on storage capacity or I/O latency at the primary site, when the real issue is the WAN link’s throughput. Remember the memory tip: “Bandwidth before boxes”—always address the replication pipe’s capacity first when RPO is missed, as no amount of local tuning can fix a choked remote link.
⚠ Common exam trap
The trap here is that candidates focus on the disk I/O latency or storage utilization issues, which are performance concerns, rather than recognizing that the saturated replication link is the direct cause of the RPO failure and must be addressed first.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Upgrade the replication link between primary and DR sites to a higher bandwidth connection
The immediate issue preventing the organization from meeting its RPO of 1 hour is the saturated replication link, which causes replication lag of up to 3 hours. Upgrading the link to a higher bandwidth connection directly addresses the bottleneck, reducing replication time and enabling the RPO to be met. Other options, while potentially beneficial, do not resolve the primary cause of the RPO failure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Upgrade the SAN fabric switches to support higher throughput and reduce disk I/O latency
Why it's wrong here
Reducing disk latency improves performance but does not address the replication lag that is causing the RPO breach.
- ✗
Add additional storage capacity to the DR site to reduce storage utilization
Why it's wrong here
Adding DR storage capacity does not resolve the replication link saturation; it only addresses potential future capacity issues.
- ✗
Implement more frequent incremental backups and reduce retention period to free up storage
Why it's wrong here
More frequent backups increase replication traffic, worsening the saturation, and do not address the root cause of replication lag.
- ✓
Upgrade the replication link between primary and DR sites to a higher bandwidth connection
Why this is correct
This directly addresses the replication lag, reducing it to meet the 1-hour RPO, and is the most urgent action to ensure disaster recovery objectives.
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Variation 1. Given this configuration, which is the PRIMARY concern?
medium- A.Data change rate exceeds bandwidth
- B.RTO may not be achievable
- C.Synchronous replication may impact application performance
- ✓ D.Bandwidth may be insufficient to meet RPO
Why D: The primary concern is that bandwidth may be insufficient to meet the Recovery Point Objective (RPO). In synchronous replication, every write must be acknowledged by the remote site before the local write completes, so the link bandwidth must be at least equal to the peak data change rate. If bandwidth is lower, replication cannot keep up, causing the RPO (maximum acceptable data loss) to be violated as the backlog grows. This directly threatens the organization's ability to recover data within the defined time window.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISA practice question is part of Courseiva's free ISACA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CISA exam.