There is no use in having the whole ZFS pool with backups if you won't use it for your repositories. Backup for the private repositories is trivial - just create a repo on the server and push to it. But how do we add a new repository if one already has a remote (e.g. on GitHub)?
First step is to check current remotes. This information will come in handy a bit later
> git remote -v
origin firstname.lastname@example.org:medo64/QText.git (fetch)
origin email@example.com:medo64/QText.git (push)
Next step is to create a bare backup repository, followed by adding both current and new destination as the push URLs:
> git init --bare //ring/Repositories/QText.git
> git remote set-url --add --push origin firstname.lastname@example.org:medo64/QText.git
> git remote set-url --add --push origin //ring/Repositories/QText.git
> git push -u origin --all
Reason behind the double add is due to Git "forgetting" its default location once the first manual add is executed. Any further update will not be affected.
Now a single push command will update both repositories.