I am using daemontools and was having trouble with the log files. The log script was not being supervised, nothing I did seemed to make it work. svstat /service/test/log returned unable to open supervise/ok: file does not exist.
The problem was that svscan had picked up on my service before the log directory existed. And no matter what I did (including restarting the service), it wasn’t noticing the log directory. I couldn’t get it to notice the filesystem change because I made real directories in /service for each service, not symlinks.
One solution would be to reboot, but rebooting a unix box is equivalent to admitting failure. I stopped my service, moved the service files to /var/local/services/test, then symlinked the service directory into /service.