A backup can help a service continue when its usual way of working becomes unavailable. Separate arrang provide stro protection wh their lik failures dep on diff causes rat than sha hidden weakn that co disable every option at the same moment. Two copies of a file on the same damaged device may be less useful than they first appear. Planning should therefore ask how the alternatives could fail, not merely count how many exist. It also matters whether people can reach the backup and use it when the normal process has stopped.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.