The scenario describes heavy performance degradation during specific times, which indicates a resource bottleneck under peak load. When a Virtual Machine's (VM) workload demands more memory than the physically allocated RAM (8 GB in this case), the hypervisor or the VM's guest operating system will resort to swapping. This process involves moving memory pages to much slower disk storage to free up RAM. The high latency of disk I/O compared to RAM access causes a severe and noticeable drop in application and system performance, a condition often called "thrashing." This directly matches the symptoms described.

A. The host requires additional physical CPUs.

While CPU contention can cause slowdowns, the "heavy degradation" described is more characteristic of memory exhaustion and swapping than CPU queuing.

B. A higher number of processes occur at those times.

This describes the cause of the increased load but is not the root explanation for the performance failure; the failure is the system's inability to handle that load due to a resource limit.

D. The storage is overutilized.

This is a possible outcome of heavy swapping but not the root cause. The primary issue is the lack of RAM, which forces the system to overutilize storage for swapping operations.

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1. VMware Official Documentation. (2023). vSphere Resource Management for VMware vSphere 8.0. Chapter 8: Managing Memory Resources

Section: Host-Level Swapping. The guide states

"Host-level swapping is a last resort for ESXi to reclaim memory... The performance of a virtual machine can degrade significantly when the guest operating system or the host swaps." This confirms that swapping due to memory pressure causes severe performance degradation.

2. University Courseware. Arpaci-Dusseau

R. H.

& Arpaci-Dusseau

A. C. (2018). Operating Systems: Three Easy Pieces. Arpaci-Dusseau Books. In Chapter 22

"Swapping: Mechanisms

" the text explains that when physical memory is full

the OS will swap pages to disk. Chapter 23

"The Memory Hierarchy

" quantifies the performance difference

noting that accessing disk is orders of magnitude (100

000x) slower than accessing DRAM

which explains the "heavy" performance degradation.

3. Peer-Reviewed Academic Publication. Waldspurger

C. A. (2002). Memory resource management in VMware ESX server. In Proceedings of the 5th symposium on Operating systems design and implementation (OSDI '02). USENIX Association

USA

181–194. Section 4.4

"Swapping

" explicitly states

"As a last resort

ESX can reclaim memory by swapping pages from a VM to a server swap file... Since swapping requires disk I/O

it can impose a large performance overhead." This foundational paper validates that swapping is a high-overhead

last-resort mechanism.