*** MULIG SPAM*** Re: Distributed setup with realtime failover/balancing

[jonas at vrt.dk]

Hello

> >> Hmm well it might be overkill, but definitely not for the above
> >> reason. Your
> >> describing the normal basic smtp loadbalancing/failover that mx records
> >> provides, which is fine. The problem is in a mailscanner/mailwatch
> setup
> >> there are more components than simply the smtp incbound traffic. After
> a
> >> remote server have send a mail to either of the mx records, the mail is
> >> stored temporary on one of the boxes, if that box goes down, that mail
> >> and
> >> any mail quarantined on the box is unavailable to users. Which is not
> >> acceptable.
> 
> How is an LVS solution going to solve that?  However you implement it
> the connection will be load balanced across the MailScanner boxes and
> they will spool to disk.  Once the connection is closed the LVS is no
> longer involved.
> 
> If this is a requirement then you will have to move to something that
> analyses the email as it is being spooled to disk (e.g. a milter). Also
> how are you going to track whether a message has been delivered or not?
> 
I am sorry, I have not been very clear. The main reason for me to desire a
distributed setup, is to have the quarantine directory always be available.
That's where DRBD comes in. ultramonkey/lvs/heartbeat is just to spread out
the load on apache and mysql. And also to facilitate failover.

Mails that are in actual transit (meaning in the in or outgoing queues) are
more acceptable to loose, than users not being able to release mails from
the quarantine. At least they are for me.

I hope that explains it a little bit better.

Best regards

Jonas Larsen