Backup is a process of making a copy of your current data and storing it in another place. If the original data is lost or damaged, the backed up data can be restored, i.e., copied back. Backing up is useful when you need to make system-wide changes that can affect your data or server performance (for instance, upgrade the OS that Plesk is running on). Backing up is also done for safety purposes, i.e., to avoid losing data in case of unforeseen circumstances (e.g., server HDD malfunction).
Plesk backup/restore utilities offer you the following data backup and restoration options:
domain_bu.exeutility, which is accessed through command line interface. You can also backup and restore individual domains using Backup feature available through Plesk control panel GUI.
For more information about these utilities, refer to How To Back Up And Restore Your Plesk Data section.
To find out what specific data is backed up/restored using these options, refer to the What Plesk Data Is Backed Up And Restored section.