source – http://0pointer.de/blog/projects/why.html
| sysvinit | Upstart | systemd | |
|---|---|---|---|
| Interfacing via D-Bus | no | yes | yes |
| Shell-free bootup | no | no | yes |
| Modular C coded early boot services included | no | no | yes |
| Read-Ahead | no | no[1] | yes |
| Socket-based Activation | no | no[2] | yes |
| Socket-based Activation: inetd compatibility | no | no[2] | yes |
| Bus-based Activation | no | no[3] | yes |
| Device-based Activation | no | no[4] | yes |
| Configuration of device dependencies with udev rules | no | no | yes |
| Path-based Activation (inotify) | no | no | yes |
| Timer-based Activation | no | no | yes |
| Mount handling | no | no[5] | yes |
| fsck handling | no | no[5] | yes |
| Quota handling | no | no | yes |
| Automount handling | no | no | yes |
| Swap handling | no | no | yes |
| Snapshotting of system state | no | no | yes |
| XDG_RUNTIME_DIR Support | no | no | yes |
| Optionally kills remaining processes of users logging out | no | no | yes |
| Linux Control Groups Integration | no | no | yes |
| Audit record generation for started services | no | no | yes |
| SELinux integration | no | no | yes |
| PAM integration | no | no | yes |
| Encrypted hard disk handling (LUKS) | no | no | yes |
| SSL Certificate/LUKS Password handling, including Plymouth, Console, wall(1), TTY and GNOME agents | no | no | yes |
| Network Loopback device handling | no | no | yes |
| binfmt_misc handling | no | no | yes |
| System-wide locale handling | no | no | yes |
| Console and keyboard setup | no | no | yes |
| Infrastructure for creating, removing, cleaning up of temporary and volatile files | no | no | yes |
| Handling for /proc/sys sysctl | no | no | yes |
| Plymouth integration | no | yes | yes |
| Save/restore random seed | no | no | yes |
| Static loading of kernel modules | no | no | yes |
| Automatic serial console handling | no | no | yes |
| Unique Machine ID handling | no | no | yes |
| Dynamic host name and machine meta data handling | no | no | yes |
| Reliable termination of services | no | no | yes |
| Early boot /dev/log logging | no | no | yes |
| Minimal kmsg-based syslog daemon for embedded use | no | no | yes |
| Respawning on service crash without losing connectivity | no | no | yes |
| Gapless service upgrades | no | no | yes |
| Graphical UI | no | no | yes |
| Built-In Profiling and Tools | no | no | yes |
| Instantiated services | no | yes | yes |
| PolicyKit integration | no | no | yes |
| Remote access/Cluster support built into client tools | no | no | yes |
| Can list all processes of a service | no | no | yes |
| Can identify service of a process | no | no | yes |
| Automatic per-service CPU cgroups to even out CPU usage between them | no | no | yes |
| Automatic per-user cgroups | no | no | yes |
| SysV compatibility | yes | yes | yes |
| SysV services controllable like native services | yes | no | yes |
| SysV-compatible /dev/initctl | yes | no | yes |
| Reexecution with full serialization of state | yes | no | yes |
| Interactive boot-up | no[6] | no[6] | yes |
| Container support (as advanced chroot() replacement) | no | no | yes |
| Dependency-based bootup | no[7] | no | yes |
| Disabling of services without editing files | yes | no | yes |
| Masking of services without editing files | no | no | yes |
| Robust system shutdown within PID 1 | no | no | yes |
| Built-in kexec support | no | no | yes |
| Dynamic service generation | no | no | yes |
| Upstream support in various other OS components | yes | no | yes |
| Service files compatible between distributions | no | no | yes |
| Signal delivery to services | no | no | yes |
| Reliable termination of user sessions before shutdown | no | no | yes |
| utmp/wtmp support | yes | yes | yes |
| Easily writable, extensible and parseable service files, suitable for manipulation with enterprise management tools | no | no | yes |