After I backed up my vault qubes to Blu-ray - R I saw someone mention in passing that it is recommended to also back up template VNs in case you need to restore the vault on a system that doesn’t use them due to depreciation in the future. Is there any other general advice on ensuring compatibility with future set ups?
e.g Should I use Debian instead of Fedora since it is supported longer? Should I also back up an installation ISO of Qubes 4.2?
Or am I just making things difficult for no reason backing up entire vault qubes like this instead of just using normal backups. It seems like a convenient way of picking up where I left off in case of catastrophic failure but maybe it is more trouble than it is worth.
You do not need to back up the templates, since restore explicitly
allows you to restore a qube without the original template. The
default template will be used if the original is not available, and you
can then apply any other template on your system.
This is particularly true when moving between Qubes versions.
Use whatever templates you are comfortable with. You may find that
changing Fedora templates brings you some issues, but the same may apply
when moving between Debian. It’s just that that takes longer.
You may choose to do this, but old ISO are archived if you should need
them.
The important thing is to back up your data on a regular basis. You may
choose to do this using Qubes backup, or some other tool. It’s the data
that counts.
Qubes backups are good for dealing with Qubes transfers or restoration
after a catastrophic failure. They are not good for data recall, where
file system backups are better.
I never presume to speak for the Qubes team.
When I comment in the Forum I speak for myself.
The Qubes backup system is designed with emergency disaster recovery in mind. No special Qubes-specific tools are required to access data backed up by Qubes. In the event a Qubes system is unavailable, you can access your data on any GNU/Linux system by following these instructions:
Therefore, it is not necessary to back up templates (assuming they contain no user data) or Qubes ISOs. However, you may wish to do so in order to make restores faster or more convenient.