alt Hacker NewsThe simple answer is have 2. If the cost per unit is low enough than deploying 2 PiHoles is trivial.
The developers could make users' lives easier by implementing a clustering option that syncs the 2 out of the box. For static deployments, where you don't change the config too often, it's still decent as it is.
I did the same (until my RPi zero stopped working). Both the devices share same vertical IP address and if one ever went down, the other would take over without any delay.