DNS caches that support partitioning ?

Mark Andrews marka at isc.org
Sun Aug 19 21:37:31 UTC 2012

In message <DDF607B5-415B-41E8-9222-EB549D3DBB0C at semihuman.com>, Chris Woodfiel
d writes:
> What Patrick said. For large sites that offer services in multiple data =
> centers on multiple IPs that can individually fail at any time, 300 =
> seconds is actually a bit on the long end.
> -C

Which is why the DNS supports multiple address records.  Clients
don't have to wait a minutes to fallover to a second address.  One
doesn't have to point all the addresses returned to the closest
data center.  One can get sub-second fail over in clients as HE
code shows.

As for the original problem.  LRU replacement will keep "hot" items in
the cache unless it is seriously undersized.


Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org

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