Re: [Exim] Delivery optimization tips for large lists ?

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Author: Pete Naylor
Date:  
To: exim-users
Subject: Re: [Exim] Delivery optimization tips for large lists ?
On Sat, 9 Oct 1999, Peter Radcliffe wrote:

> Pete Naylor <pete@???> probably said:
> > are - generally it's because they assume it hasn't improved since SunOS
> > 5.5. SunOS 5.7 has a partial resolver rewrite which allows for
> > concurrent DNS requests. Configured properly, nscd is a great tool.
>
> The lack of concurrent lookups was a minor one of my complaints.


It was my only complaint.

> Being set up to cache negative responses by default is another


Nobody can help you if you misuse the software. You should configure it
appropriately for your needs.

> and
> caching A records at a level that doesn't understand round robin DNS
> is another


That would be a nice feature to add, but it's not terribly important.

> - it stopped one of my mailservers being able to fallback
> to a backup mailserver on many occasions until I forcibly ripped it
> out being one of the more major complaints.


Please explain in more detail. I fail to see how round robin DNS is
related to providing multiple mail servers with any sort of failover
mechanism so I have to assume that this is another case of misuse.

> If you need it for passwd or other caching, fine (you can set it to
> just cache the things you want it to cache), but using it to cache DNS
> is broken. This is what caching name servers are for.


They're very different applications though, and each has its pros and
cons. An ideal solution probably involves using both (though I wouldn't
necessarily run named on the same host).

-- 
/*-------------------------------------------------------------*
 * Peter James Naylor ## SysAdmin, Supernal Technologies, Inc. *
 *-------------------------------------------------------------*
       * pete@??? ## <http://www.supernal.net> *
       *------------------------------------------------*/