Distributed setup with realtime failover/balancing

[Alex Broens]

On 1/11/2007 10:10 AM, jonas at vrt.dk wrote:
> Hi all
> 
>  
> 
> I am currently running a MAilscanner/mailwatch system on a single server
> which works perfect.
> 
>  
> 
> I however have the need to make my setup distributed, for me meaning the
> following.
> 
>  
> 
> I need a 2 node distributed system. Where I have 2 smtp servers(exim), 2
> mailscanners, 2 mailwatch interfaces and 1 distributed mysql database.
> 
>  
> 
> I plan on using ultramonkey (http://www.ultramonkey.org
> <http://www.ultramonkey.org/>  ) to setup load balancing and failover. It
> uses LVS and heartbeat to do that.
> 
>  
> 
> I have the mysql problem pretty well figured out. I’m gonna run a so called
> master-master replication between the 2 servers. Meaning any change in the
> tables will be instantly replicated to the other server, so should one go
> down the chance of data loss is very slim.
> 
>  
> 
> Regarding the quarantine I also need some more or less complex solution,
> since I don’t want to use local quarantine directories for each server. The
> reason is that I do NOT want a local quarantine directory on each server. I
> do not want that because then I do not have access to release mails
> quarantined by the server that is down (Even if if setup some rsync script
> it isn’t real-time so data loss is very likely) There for I plan on using a
> system like drbd (http://www.drbd.org/ ) or another similar distributed file
> system. That means you get a so called “network raid mirror” where all disk
> io is replicated across a network so if 1 server fails all data is still
> accessible on the other machine. This would enable me to never loose the
> ability to release quarantined mails.
> 
>  
> 
> What I am looking for is comments from fellow mailscanner/ mailwatch users
> regarding this solution. Is it a dumb way to do it? Are there better ways to
> archive the whole thing, or part of it?
> 
>  
> 
> I hope somebody has some input.
> 

Whatever, in a master/master mysql setup do not replicate mysql based 
bayes.  Conflicts show up real fast and it will stop all your replication.

Alex