Return two locations or low TTL [was: DNS caches that support partitioning ?]

Chris Adams cmadams at
Mon Aug 20 12:47:34 UTC 2012

Once upon a time, Patrick W. Gilmore <patrick at> said:
> * How many applications are even aware multiple addresses were returned?

Most anything that supports IPv6 should handle this correctly, since
getaddrinfo() will return a list of addresses to try.

> * How do you guarantee sub-second failover when most apps will wait longer 
>   than one second to see if an address responds?

That's a bigger issue.  Also, for web services, the application might
wait, but the end-user usually won't (if the site doesn't come up in a
second, they move on to the something else).

Chris Adams <cmadams at>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.

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