systemd and SysV

Systemd and SysV are both init systems used in Unix-like operating systems such as Linux.

List of distributions:

  • Ubuntu - systemd
  • Debian - systemd
  • CentOS - systemd
  • Fedora - systemd
  • Red Hat Enterprise Linux (RHEL) - systemd
  • openSUSE - systemd
  • Arch Linux - systemd
  • Linux Mint - systemd
  • Manjaro - systemd
  • Elementary OS - systemd


  • The traditional init system used in Unix-like operating systems. It follows the System V Unix conventions.
  • SysV init relies on shell scripts located in specific directories (/etc/init.d/ and /etc/rc.d/) to start and stop services.
  • SysV init starts services sequentially, meaning that one service has to be fully started before the next one begins.
  • Limited parallelism in SysV init can lead to slower boot times, especially on systems with many services.
  • Dependency management in SysV init is often managed manually in script files, which can become complex and error-prone.


  • A more modern init system designed to overcome some of the limitations of SysV init.
  • Uses unit files (*.service, *.socket, etc.) to describe how services should be started, stopped, and managed. These unit files can include dependency information and other configurations.
  • Allows for parallel startup of services, improving boot times by starting services in parallel when possible.
  • Systemd handles dependency management automatically based on the information provided in unit files, simplifying service management.
  • Systemd includes features for enhanced logging (journalctl) and monitoring of system services, making it easier to troubleshoot and manage the system.
  • Systemd includes many other features such as socket activation, on-demand starting of services, cgroup-based process tracking, and more.