We’ve watched businesses get burned many times on this issue. A backup is a separate ‘copy’ from which to restore. A RAID array or other redundant systems are important, but if they fail, there is nothing to restore. We recommend having a RAID array, especially on a server. This allows drives to ‘mirror’ data across the group of drives, so if a drive fails, it can be replaced and the array can rebuild without having to restore from a backup. BUT, if the RAID fails or becomes corrupt, you must have a backup from which to restore.
There’s more than one type of backup—there are flat file backups where you have a copy of the file and can restore from the copy. BUT, you have to have a machine with the software installed in order to open the restored files; assuming the data is there and was not corrupted! There are image-based backups which include the Operating System and other software; this is ideal and saves so much time. – CMW
How to backup your data is so important, Cathy made a 2-minute video message: Bad Guys Are Out There!