The Linux agent tracks CPU, memory, disk I/O, and network. Roughly two dozen metrics are collected automatically and integrated into the load-test reports, then plotted against response-time degradation. The metrics are normalized to the same vocabulary the Windows agent uses, so a Linux host and a Windows host compare directly in one dashboard.
CPU, memory, and disk are captured in the Free edition on every monitored host. Network and TCP metrics, plus process queue length, are part of the Cloud full-metric set, alongside AWS CloudWatch and Dynatrace integration. There is no metric-selection step to configure: the agent collects its full set automatically.
Mixed fleets are the norm: a Linux database server behind a Windows web tier, or the reverse. The Linux agent normalizes its metrics to the same names and units the Windows and AIX agents use, so hosts of different platforms appear in the same Server Performance overview and their curves line up on the same axes. There is no mental conversion between platform-specific counter names while you are trying to find the saturated host.
The Analytics Dashboard plots every collected metric on the same x-axis as response time and flags any resource whose curve correlates above 0.94 with the slowdown. On Cloud the AI report writes the bottleneck-source paragraph from those flags: which resource saturated, on which host, at which user level the response time went vertical.
Run a load test against your Linux hosts and watch the metrics line up.
The monitoring agent ships in every WPLoadTester 7 install and captures CPU, memory, and disk for free. The full network and TCP set is part of the Cloud edition. Download it to see your own server metrics correlated against response-time degradation.
Comparing tiers? See the Free vs Cloud split.