Server virtualization has improved deployment speed and operating-cost efficiency for many IT applications. Which of the following architectures are…

The question describes the "noisy neighbor" effect, a common performance challenge in virtualized environments where multiple virtual machines (VMs) share the same physical host hardware. The performance of an application under test can be negatively impacted by other resource-intensive, unrelated VMs on the same host. Multi-tier, distributed, and cloud-based architectures are modern system designs that heavily rely on server virtualization for scalability, resource management, and cost-efficiency. Components of these systems are frequently deployed as VMs or containers across a pool of shared physical servers, making them highly susceptible to the "noisy neighbor" problem.

ii. Mobile: This architecture refers to the application running on the end-user's device, which is not a shared, multi-tenant server environment where this specific virtualization risk occurs.
iii. Single Computer: This architecture, by definition, does not inherently involve multiple unrelated virtualized servers competing for resources on common host hardware.

1. ISTQB® Certified Tester Foundation Level Performance Testing Syllabus Version 1.0 (2018), Section 3.2.2, "Performance Risks in Specific Architectures". This section explicitly links performance risks like resource contention to these architectures. For Cloud-based systems, it states: "Performance can be affected by other tenants on the same hardware ('noisy neighbors')." Multi-tier and Distributed systems are also noted for their complexity, which is often managed via virtualization, introducing similar risks.

2. Jamshidi, P., Ahmad, A., & Pahl, C. (2013). Cloud Migration Research: A Systematic Review. IEEE Transactions on Cloud Computing, 1(2), 142-157. DOI: 10.1109/TCC.2013.10. This paper discusses the foundational role of virtualization in cloud computing (Section III-A) and the associated performance challenges, including resource interference in multi-tenant environments.

3. Ferdman, M., et al. (2012). Clearing the Clouds: A Study of Public Cloud Performance and Variability. Proceedings of the 17th International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS '12), 37-48. DOI: 10.1145/2150976.2150982. This academic study empirically demonstrates the "noisy neighbor" problem (referred to as cross-VM interference) in public cloud environments, which are prime examples of distributed, multi-tier systems built on virtualization.