[CentOS] how to increase DNS reliability?

Thu Jul 25 21:17:20 UTC 2019
Giles Coochey <giles at coochey.net>

On 25/07/2019 20:39, John Pierce wrote:
> On Thu, Jul 25, 2019 at 10:32 AM hw <hw at gc-24.de> wrote:
>> I can't help it when the primary name server goes down because the UPS
>> fails
>> the self test and tells the server it has 2 minutes or so left in wich case
>> the server figures it needs to shut down.  I wanted better UPSs ...
> critical infrastructure servers should have redudant PSUs, on seperate UPSs.

Separate DNS servers must be on a different subnet according to RFC2182 

Secondary servers must be placed at both topologically and
    geographically dispersed locations on the Internet, to minimise the
    likelihood of a single failure disabling all of them.

I know that UPSs are physical, and subnets are logical, but the 
reasoning behind the requirement is due to having to be on a different