> On 23-4-2010 11:19, Michiel van Es wrote:
>>
>>
>> Angelo Höngens wrote:
>>> On 22-4-2010 20:28, Michiel van Es wrote:
>>>> Yes
>>>> That is the default smtp failover setup but I want to balance the load
>>>> via a load balancer setup
>>>> Mx records can not balance load
>>>
>>> If you have 2 mx records with the same priority, your load should be
>>> balanced..
>>>
>>> Or you could have a single mx record pointing to a hostname which has 2
>>> A records.. DNS round robin will take care of the balancing.
>>>
>>> That is why there are almost no smtp balancers, because it is not
>>> needed. In the 1980's they already designed smtp for balancing and
>>> failover. For other protocols this was not so easy, that's why people
>>> wrote http balancers :)
>>>
>> Yes I understand, but what about settings features as weight or doe
>> advanced load balancing?
>
>
> You can't do advanced balancing, true..
>
> If you *must* have weight, you could go for the host records approach.
> Make 1 MX record pointing to mx-in.example.com, and create three host
> records: mx-in -> x.x.x.1, mx-in -> x.x.x.1, mx-in -> x.x.x.2. This way,
> server 1 gets around 66% of the sessions, and server 2 gets around 33%
> of the sessions.
>
>
>> What is one of the mailservers are broken and you want to take it offline.
>> With a normal TTL in dns it can take 1 or 2 days before other
>> mailservers know it should not send a mail to that server and use the other.
>> I like load balancers because they can let you decide how traffic must flow.
>
>
> No problem if you use the MX way, just take the server offline, no need
> to change dns.. Remote mail servers will just try one mail server, and
> if it's down, they will use the other, failover is built into the way
> smtp and dns work together.
>
>
> I'm not saying you should not do what you are doing. If you really want
> to use your own balancer, and you feel better doing that, then by all
> means please do. What's I'm saying is that people have been balancing
> smtp servers for 30 years using the ways they though of in the 80's, and
> since that works for most organisations, it might work for you. KISS.
>
> Don't look blindly at the tools you're using, but choose the tools you
> need based on the goal you're trying to reach. Ah, who am I kidding, I'm
> just an IT-nerd wanting to play with cool balancers as well..
That is the whole idea ;)
I know DNS load balancing works (I have it up & running right now) but I
want to do load balancing with a load balancer..I want to have a setup
which is flexible and a blueprint for let say: a 500+ mailserver setup
with very heavy load (think Google or Hotmail).
Michiel
>
>
Received on 2010/04/23 11:36
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