Hm, there really isn't a need to run separate backups of ArcGIS Server and the ArcGIS Data Store, since those backups are included in the backup of the WebGIS DR tool. We can look into whether we should remove those bullets.
If an upgrade fails, then yes you can't restore a backup taken with the DR tool to get back to a functioning state. You'll need to uninstall, reinstall, and configure the software at the same version you were upgrading from before you restore the backup.
Aaron Booterbaugh, can you expand on your comment below?
Once you upgrade and have to go back without a VM snapshot the new install of the older software has different keys and the DR does not work in this case.
What keys are you referring to? The DR tool simply calls into the import site operations available for each component. As long as the software is installed, authorized, and configured, the restore will go through. This likely takes more time than reverting to a VM snapshot. We put out a blog on minimizing downtime and risk when upgrading which can be followed if resources permit:
Minimize downtime when upgrading ArcGIS Enterprise
