nanog mailing list archives

Re: ttl for ns


From: Niels Bakker <niels=nanog () bakker net>
Date: Fri, 13 Aug 2004 17:33:29 +0200


* mcgehrin () reverse net (Matthew McGehrin) [Fri 13 Aug 2004, 16:46 CEST]:
1.    It's a financial issue. In the event of an emergency or an server 
failure, how many hours can you financially be offline. Are your customers 
willing to wait up to 2 days for their DNS caches to update with the new IP 
address?

In the event of a server failure I suggest you add its IP address as an
alias to a non-deceased host.  You kept backups of your master zone files
on another machine, didn't you?


A very busy domain might benefit from having a higher TTL value for their 
nameserver's but having a lower TTL for hosts, so that you minimize your 
downtime, in the event of a server failure. For example, when Akamai was 
having DNS issues, content providers with low TTL's were able to switch to 
secondary nameservers faster, than zones with using a higher TTL.

Assuming you're talking about a specific incident not too long ago:

To me it looked more like those who had actually spent thought on what
to do in the case of a large, longer Akamai failure had less impact when
that failure occurred.


        -- Niels.


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