There is no “best way” to backup the My Cloud. Each backup method has its pluses and minuses. The easiest way is to use Safepoint or Backup, depending on which firmware version one is using. Safepoint will allow one to backup to either an attached USB hard drive or to a location on the local network. Using software like Acronis True Image, which is generally used to backup a computer, to backup the My Cloud will generally only backup the user data on the My Cloud. Further it will require the use of a computer that is running Acronis to perform the backup and the backup speed would be dependent on the network speed.
The current firmware does have a bug that causes the USB drive name to be duplicated causing the firmware to not see the Safepoint saved to the USB drive. The solution to this bug is to remove the duplicated USB share names and rename the USB share back to its original name which causes the firmware to see the Safepoint on the USB drive.
There are alternative methods, like using SSH to issue the Rsync command, to backup the My Cloud. There is some discussion on alternatives to Safepoint at the following thread:
https://community.wd.com/t/alternative-to-safepoint-reposted/140685
