Re: [Exim] Split mail hub and MX questions

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Author: John Horne
Date:  
To: Exim Users List
Subject: Re: [Exim] Split mail hub and MX questions
On 01-Sep-00 at 11:24:43 Philip Hazel wrote:
> On Thu, 31 Aug 2000, Mike Meredith wrote:
>
>> * An idle backup machine. Our backup machine is quite a capable box,
>> and it may cause problems if people don't understand what it is there
>> for (seeing it as wasted resources).
>
> You don't need to have one "master" and one "backup" just for mail
> hubbing. They can be equals. If they have the same MX priority, or are
> accessed via two A records, you should find that traffic is split
> between them. We use 4 hosts like this for the cam.ac.uk domain.
>

Generally, yes but in our case we have specific per-user data and majordomo
lists on the mailhub. These are dealt with/modified by humans and (in
theory) both mailhubs should have exact copies of the data. In practice this
won't happen - e.g. a list owner subscribes a user; this happens on mailhub
'a' but mailhub 'b' knows nothing about it; that user sends a message to the
list - gets mailhub b - which then rejects the message since he is not a
member of the list. It's easier to have the 'master' system looking after
the lists. The per-user data I can 'fiddle with' so that most of it is
duplicated - again 'vacation messages' is another example; since the 'once'
database is only updated on one system.

John.

------------------------------------------------------------------------
John Horne, University of Plymouth, UK           Tel: +44 (0)1752 233914
E-mail: jhorne@???
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