If you have no spares (or not at least 2 spares), you will need to wipe the system and start from scratch. Boot to the maintaince menu and select #4a.
You will then need to re-run setup, re-install licenses, etc.
If you have at least 2 spares you can create a RAID-4 volume (or aggregate) and copy your root volume data over to it, reset the root volume, reboot the controller, the blow away the old aggregate.
Tech Support can help you with either of these procedues.
Hope this helps.