1. Wrong File Permissions
Magento Backup always reset your files and directories to the wrong file permissions after a backup is completed.
The file permission for all files in our server should be set to 644 and all directories to 755.
Magento Backup attempt to use insecure permissions like 666 and 777 which can also cause your website to throw up a 403 Error (Forbidden).
2. Timeout and Incomplete Backup
As Magento Backup is running as a "user" and not at the server level, it can timeout which causes incomplete backups.
3. Slowdown to Your Website
Magento Backup will use the same resources as your website, especially for Web Hosting clients and this can cause slowdown to your website.
We recommend our clients to use the backup systems provided by us, especially cPanel Full Backup which is the most complete backup of your account.
Interm Solution for Wrong File Permissions
If you still want to use Magento Backup, there is an interim solution to fix the most important problem which is the wrong file permissions as stated in point #1 above.
Important Note: This is a manual hack which may cause issues if you have done any customization to your Magento store and it will be overwritten during a Magento upgrade.
In your Magento directory, copy this file:-
Open up File.php and look for this line:-
public function open($mode = \'w+\', $chmod = 0666)
Replace it with this line:-
public function open($mode = \'w+\', $chmod = 0644)
Save the file and the next Magento backup will reset all file permissions to the correct and safe file permission of 644 instead of 666.