below

below is an interactive resource monitoring tool designed for modern Linux systems that captures and analyzes system performance data over time. Unlike traditional monitoring tools, it offers a unique time-traveling capability that lets you review historical system behavior alongside live data.

Key capabilities include:

• Hardware monitoring - Track CPU, memory, disk, and network resource utilization
• Cgroup management - View and analyze cgroup hierarchies and resource constraints
• Pressure metrics - Monitor pressure stall information (PSI) to identify system bottlenecks
• Multiple viewing modes - Switch between live system monitoring, historical replay, and snapshot analysis
• Data export - Generate reports in JSON, CSV, OpenMetrics and other script-friendly formats
• Persistent recording - Continuously collect system data with optional systemd/OpenRC service integration

The tool excels at answering performance questions by letting you replay historical data from minutes or hours ago, making it invaluable for investigating performance incidents after they occur. It works exclusively with cgroup2 on modern Linux distributions and provides a cleaner, more intuitive interface compared to legacy monitoring tools. Available as packages for Fedora, Alpine Linux, Gentoo, and Amazon Linux, or installable from source via Cargo.