My server will run only weekly for 2 hours for backup purposes. After I finished the backuping I pull out the power plug from the power outlet. How does a server power supply withstand unto toggling the power? Will it fail shortly?
Running for two hours every week means one start and one per week. Any power supply should be able to handle that.
But I would suggest that you use a power strip that has a switch on it, and use the switch. Actually plugging the plug could wear the plug and/or the socket on the long run.