Easy, fast to configure. For example, services available are at /etc/sv. To add the ufw service:
sudo ln -s /etc/sv/ufw /var/service
And to remove the service, just delete the link:
sudo rm -r /var/service/ufw
Ranked in these QuestionsQuestion Ranking
Pro Fast, parallel startup
After the system's one time tasks (stage 1) are done, the system services are started up in parallel. The operating system's process scheduler takes care of having the services available as soon as possible.
Pro Small and Unix-like
One of the runit project's principles is to keep the code size small. As of version 1.0.0 of runit, the runit.c source contains 330 lines of code; the runsvdir.c source is 274 lines of code, the runsv.c source 509. This minimizes the possibility of bugs introduced by programmer's fault, and makes it more easy for security related people to proofread the source code.
The runit core programs have a very small memory footprint and do not allocate memory dynamically.
Pro Easy to use
Simple scripts linked to the proper directory is all that's needed to bring a service up at boot, and everything is up and running quickly.
Pro Runs on every POSIX system
Pro Init purity - does what an init system must do and nothing more
UNIX philosophy, easy to add new services, easy to manipulate, really fast.
Pro Supported by several Linux plumbers
Myself included. Development is no longer stalled.
Pro Faster boot time than with systemd
Faster on older systems, especially those running on HDDs.
Pro Fast and easy to use
Con Not GPL
Con Development stalled
Last patch was back in 2014.