[CentOS] how to increase DNS reliability?

Thu Jul 25 19:45:12 UTC 2019
mark <m.roth at 5-cent.us>

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.
> my last rack builds, I had 2 Eaton PowerWare 7KVA 4U UPS's in the bottom
> of each rack.  one fed the left side PDUs, the other fed the right side
> PDUs, and each server had redundant PSU's, one plugged into each PDU.
> those Eaton UPS's had hotswappable batteries, too.

*shrug* All UPSes have hot-swappable. Mine beep while you disconnect the
batteries, pull out the sled, replace all 8, shove it back in, and
reconnect, and it shuts up.

For those that haven't done it, though, DO NOT BELIEVE WHAT ANYONE SAYS,
DO NOT USE *ANYTHING* BUT HR (high rate) batteries in a UPS (maybe in a
home one, but...). APC, for example, simply stays red, and insists that
you still need to change them. *Good* battery vendors know this.