[Outages-discussion] DNS server caused provincial-wide outage

[Joe Abley]

On 26 May 2015, at 15:57, Bill Wichers wrote:

> It's pretty easy to just add a second, different server into the other 
> "DNS
> Server" box on just about any OS too.
>
> I see so many users that only have one DNS server and that's another 
> recipe
> for disaster :-)

In practice, I've observed that the timeout involved in moving from one 
resolver to another is frequently longer than the attention span of the 
end-user, so in practice it's not as useful as you might think. By the 
time the OS is getting close to thinking about using the other address, 
the user has already clicked reload and stop about forty times in random 
sequence and is hunting for the right menu item to reboot the computer.

> All we do here is run a server in each physical datacenter, all on 
> different
> subnets. Those are what we give out to our customers. Chances of all 
> of them
> being offline at the same time is vanishingly small.

For extra credit, anycast both addresses between multiple sites (inside 
your own network). Then you can tolerate the loss of a single site 
without having to worry about the time taken for end-users to switch 
addresses.


Joe