Just a reminder to all of you and myself to create backups of everything.
During the weekend I've crashed my website during an update. Fatal error can't see website type of thing.
Fortunately I had a backup which I've uploaded on server.
In my case cost was few hours of downtime and few gray hairs. Make sure it won't be worse in your case.
Technical note: In my case updating wordpress plugins resulted in all this mess. Obviously it was a bit unexpected.