load balancing - email server

[Eric Anderson]

Etienne Ledoux wrote:
> On Thursday 28 April 2005 10:04, Oliver Brandmueller wrote:
> 
>>Hi.
>>
>>On Thu, Apr 28, 2005 at 09:44:12AM +0200, Etienne Ledoux wrote:
>>
>>>I have a similar setup but I use ipf (ipnat round-robin) for my load
>>>balancing, on a freebsd box infront of the machines. Works just as good.
>>
>>Never looked at it; is it able to do weighting and failover? How does it
>>detect, if a service is down on one of the machines, so that you don't
>>have every third connection failing?
>>
> 
> 
> Well I guess it's not that fancy. It's just plain vanilla round-robin load 
> balancing. I use other tools to detect services that die, queues not clearing 
> etc. I also use freevrrpd for failover. There use to be a project called 
> lload. This apparently in conjunction with ipfw could do weighted load 
> balancing but I can't seem to find that anymore. I guess it died. I'm sure 
> there might be similar projects though.

Round-robin is typically considered 'load distribution', where the load 
is evenly distributed amongst a list of hosts, but not balanced by how 
loaded the machine is or if the machine is even down.

CARP, which will be in 5.4R I believe (and is in 6.0-CURRENT now), is 
like VRRP, but with more knobs, whistles, and features.  You should look 
into CARP for this.

Eric



-- 
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Eric Anderson        Sr. Systems Administrator        Centaur Technology
A lost ounce of gold may be found, a lost moment of time never.
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