SY0-701 Question 151
Single answerConsiderations: Availability , Resilience , CostA regional healthcare provider is redesigning a patient scheduling application after several outages caused by a single ISP failure and an aging on-premises server. The security administrator must improve availability and resilience while keeping recurring costs as low as possible. The application contains sensitive data, but the immediate requirement is to ensure the service remains reachable during common infrastructure failures without purchasing a fully duplicated secondary data center. Which solution BEST meets these requirements?
- A
Deploy the application to a single high-performance on-premises server with RAID and daily backups
- B
Move the application to a cloud environment using instances spread across multiple availability zones behind a load balancer
- C
Keep the application on-premises and add a weekly full backup stored offline
- D
Purchase a second identical on-premises server and leave it powered off until the primary server fails
Show answer and explanation
Correct answer: B
Explanation
The key requirement is to improve both availability and resilience while controlling cost. High availability means minimizing downtime, while resilience means continuing operations despite failures such as a server outage or localized infrastructure disruption. Spreading application instances across multiple availability zones behind a load balancer is a well-established design pattern because it reduces single points of failure and supports failover with less administrative overhead than maintaining a fully duplicated secondary data center. In contrast, backups support recovery objectives but do not by themselves provide availability. Likewise, single-server improvements such as RAID help only with specific component failures, not broader service continuity. Guidance from major cloud architecture frameworks and high-availability best practices consistently recommends redundancy across fault-isolated zones and load balancing to improve service continuity while allowing organizations to scale costs more efficiently than building a second physical site.
- A. Incorrect.
This improves local fault tolerance for disk failure through RAID and helps with recovery through backups, but it does not adequately address availability during broader failures such as ISP outages, power issues, or server-level failures. It also leaves the organization with a single site and single connectivity path, which is a common single point of failure.
- B. Correct.
This is the best answer because distributing workloads across multiple availability zones increases resilience against localized infrastructure failures, and a load balancer helps maintain availability if one instance or zone becomes unavailable. Compared with building and maintaining a second physical site, this approach typically provides stronger availability with lower upfront capital expense and more flexible operating costs. This aligns with common cloud architecture best practices for high availability.
- C. Incorrect.
Offline backups are valuable for recovery, especially against ransomware or data corruption, but they do not keep the application available during an outage. This option focuses on recoverability rather than resilience and continuous service availability. A candidate might choose this if they confuse backup strategy with high availability design.
- D. Incorrect.
A powered-off spare server is a form of cold standby. It can reduce hardware replacement time, but failover is slower, it does not address site or ISP failure, and it still requires manual activation and synchronization considerations. It provides less resilience than a multi-zone active deployment and may not meet the requirement to remain reachable during common infrastructure failures.