Which metric indicates the efficiency of memory usage in ESXi?

The compression rate is a critical metric that indicates the efficiency of memory usage in ESXi environments. It measures the effectiveness of the memory compression feature that allows the hypervisor to compress the memory pages of virtual machines (VMs) in active use. By compressing these pages, ESXi can reduce the overall memory footprint and increase the amount of available physical memory for VMs, which enhances performance and resource utilization.

A higher compression rate suggests that more memory pages are being efficiently compressed, leading to better memory use and potentially reducing paging activities (which can negatively impact VM performance). In situations where physical memory is scarce, high compression can help maintain performance levels by avoiding excessive swapping or ballooning.

Other metrics such as the swapping rate, throughput, and IOPS focus on different aspects of virtual machine performance and storage management, thus they do not directly measure the memory usage efficiency in the same way that compression rate does. Swapping rate would relate more to how often data is moved between physical memory and disk, while throughput and IOPS are more aligned with storage performance rather than memory efficiency.