[155605] in North American Network Operators' Group
Re: DNS caches that support partitioning ?
daemon@ATHENA.MIT.EDU (Mark Andrews)
Sun Aug 19 17:38:22 2012
To: Chris Woodfield <rekoil@semihuman.com>
From: Mark Andrews <marka@isc.org>
In-reply-to: Your message of "Sun, 19 Aug 2012 13:00:49 MST."
<DDF607B5-415B-41E8-9222-EB549D3DBB0C@semihuman.com>
Date: Mon, 20 Aug 2012 07:37:31 +1000
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
In message <DDF607B5-415B-41E8-9222-EB549D3DBB0C@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
--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka@isc.org
