Today I bricked a server (long story, etc …) and I had to fix it in single user mode. The process is very simple.

  • Use the boot loader to enter in single user mode
  • Press Intro to run /bin/sh
  • mount all the zfs volumes: 
    $ zfs mount -a
  • Mount the ROOT volume read-write: 
    $ zfs set readonly=off zroot/ROOT/default
  • Fix what you broke
  • Reboot the server