iotop vs Monit

iotop is a free Linux program that identifies processes generating high input/output activity and lists them by I/O usage. The display can show accumulated I/O or bandwidth, with optional read, write, swap-in and I/O-percentage columns. Monitoring can target selected process IDs or users, or show processes and threads across the machine. Interactive and batch modes support iteration counts, configurable delays and timestamps in batch output. Command-line filters narrow processes by TID or command using a regular expression. Installation guidance covers Debian-derived distributions, Fedora, CentOS/RHEL, Void, Arch and Alpine Linux; source builds use make after development dependencies are installed. The project is GPL-2.0+ licensed, but installation and use require root access. Version 1.31 is listed as the latest release. Its tag has a verified committer signature, although the signing key has expired.

Monit is a free, open-source utility for managing and monitoring Unix systems, available for Linux, macOS, and self-hosted deployment. It watches local daemon processes and can restart a stopped process or stop one using too many resources. It checks files, directories, and filesystems for timestamp, checksum, or size changes, and tests TCP, UDP, and Unix domain sockets using protocols such as HTTP and SMTP. Scheduled program or script checks can trigger actions or alerts based on exit values. Monit tracks CPU, memory, system load, and network interfaces, and sends customizable error alerts to syslog or its own log. Its HTTP(S) interface displays service status and allows process control and monitoring changes. It works with init, upstart, and systemd, can use existing run-level scripts, and can run as PID 1 in containers. The maker says it uses statically linked OpenSSL 3.5.7 and dynamically linked PAM support.