In our lab we used a Sun 68020-powered workstation with a 150MB external SCSI drive in a 'double shoebox' along with a DC6150 tape drive for backup. The target was a VME card cage with several 68020 CPUs and miscellaneous peripherals, running VxWorks.
We used that machine for eleven months, running it 24 hours a day for nearly a year, but one night the cleaning staff used one of our power strips for their floor buffer and the breaker tripped. When we came in the next day and tried to boot the system the drive wouldn't spin up. It just hummed.
Now, this was only 150MB, but back then 150MB was a full height 5 1/4 inch collection of a half dozen platters. There was a flywhel. I gave it a spin. I felt what I imagine was the heads unsticking from the disc surface... And the drive spun up in my hand. With significant gyroscopic action. I didn't dare turn it off - an associate informed my SunOS 4.1 was booting. I carefully held it there while my associate assembled the shoebox around it.
We finished our work on that project without another power interruption, but we definitely backed up every day.
If you fail to plan, plan to fail.