How do I keep reliable backups of my site? — answered by Engineer Saeed Baatiah
Three rules: keep at least three copies, in two different locations, with one of them off the hosting itself — because a copy stored on the server that failed is no help. More important than all of it: actually test a restore at least once. Most people who discover their backups are corrupt discover it on the day they need them. Put that test in the calendar as an annual appointment.