anyone aware of a high availability setup that relies on fully redundant install?

[Greg KH]

On Sun, Apr 17, 2016 at 10:47:55AM -0400, Robert P. J. Day wrote:
> 
>   i figure this is as good a place as any to ask ... is anyone here
> aware of anyone using a linux config and install that, for the
> purposes of reliability or high availability or whatever you want to
> call it, relies on a second, completely independent installation of
> linux on the same hard drive?

ChromeOS and CoreOS do this.  There's lots of documentation on the
ChromeOS site for how this works and what is involved.