atop vs runit

atop is a free, GPL-licensed performance monitor for Linux. It uses a full-screen ASCII interface to report system and process activity at regular intervals. System-level views cover CPU, memory, swap, disk, and network activity. Process and thread views include CPU use, memory growth, disk use, and other statistics, including consumption by processes that finish during the interval. atop can save compressed raw counters for longer-term analysis, preserving daily logs for 28 days by default. The atopsar command turns those logs into system activity reports. It also reports CPU, memory, disk I/O utilization, and pressure for cgroup v2. An optional netatop kernel module adds per-process and per-thread TCP and UDP packet counts and bandwidth statistics. Displays can use bar graphs or detailed text, with columns adjusting to terminal width. Downloads list source and x86_64 RPM packages for version 2.13.0.

runit is a free Unix init scheme that supervises services and can replace sysvinit or other init schemes. It runs on GNU/Linux, BSD systems, MacOSX and Solaris, and can be adapted to other Unix operating systems. As process 1, it manages boot, normal operation and shutdown in three stages. The runsv component launches a service's run program and restarts it if it exits; an optional finish program and log service can also be used. The sv utility reports status and provides controls to start, stop, restart, pause or signal supervised services. For logs, svlogd can filter messages and write automatically rotated logs. The chpst utility changes process state and sets limits for resources such as memory, open files, process count, output size, core size and CPU time. runsvdir can start and monitor runsv processes for up to 1,000 service subdirectories. runit can supervise services alongside an existing init scheme without replacing it. The maker provides source and installation instructions, including manual installation without root access. Its documentation warns that UDP logging is unreliable and should be confined to private networks.