[CentOS] Load balancing email?

Nathaniel Hall lists at nathanhall.net
Tue Oct 25 23:52:34 UTC 2005


Benjamin Smith wrote:

>Using multiple A records is good for performance balancing, but what if one of 
>the systems fails? 
>
>Using your cocnfiguration, the delivering mail server has an "a" record and a 
>single MX, so it wouldn't try the other mail server in the case of a failure, 
>right? 
>
>Whereas, by listing multiple IPs and mx1/mx2, wouldn't the delivering mail 
>server try the other address? 
>
>Thanks, 
>
>-Ben 
>
>On Tuesday 25 October 2005 16:02, you wrote:
>  
>
>>I once did this and it worked great:
>>
>>     IN    MX    10 mx.example.com.
>>
>>mx   IN    A    192.168.1.1
>>     IN    A    192.168.1.2
>>
>>...etc.  Perfect DNS load balancing.
>>
>>Jack
>>
>>Benjamin Smith wrote:
>>
>>    
>>
>>>Currently, we have two mail relays for inbound messages, and a third for 
>>>      
>>>
>POP.
>  
>
>>>The inbound messages go thru all the CPU-intensive anti-spam stuff, and 
>>>      
>>>
>then
>  
>
>>>they relay it to the POP server for pickup.
>>>
>>>Currently, one of these is the "primary", and the other is "secondary", and
>>>I'd like them to be considered more or less as equals, since the "primary"
>>>system is getting beaten pretty hard.
>>>
>>>The DNS zone file says something like this:
>>>
>>>###############################
>>>@isp.com
>>><SNIP>
>>>               IN      MX      100 mx1.isp.com.
>>>               IN      MX      1100 mx2.isp.com.
>>><SNIP
>>>################################
>>>
>>>I seem to recall that I make them act as "equals" by simply changing this 
>>>      
>>>
>to
>  
>
>>>###############################
>>>@isp.com
>>><SNIP>
>>>               IN      MX      100 mx1.isp.com.
>>>               IN      MX      100 mx2.isp.com.
>>><SNIP
>>>################################
>>>
>>>so that they both get about the same amount of inbound messages. Has 
>>>      
>>>
>anybody
>  
>
>>>here actually done this? How well does this work as far as failover if 
>>>      
>>>
>either
>  
>
>>>system fails?
>>>
>>>-Ben
>>>--
>>>"The best way to predict the future is to invent it."
>>>- XEROX PARC slogan, circa 1978
>>>_______________________________________________
>>>CentOS mailing list
>>>CentOS at centos.org
>>>http://lists.centos.org/mailman/listinfo/centos
>>> 
>>>
>>>      
>>>
>
>  
>
In addition to the entire Cyrus system, we have 3 MX records.  All are
set to 0 with the exception of the lists server, which is set to 10.

--
Nathaniel Hall, GSEC
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.centos.org/pipermail/centos/attachments/20051025/3d477564/attachment.htm


More information about the CentOS mailing list