[CentOS] clustered mail server?

Karanbir Singh wrote:
> email is essentially an on-disk setup, so just setup any software you 
> want ( I recommend roundcube over squirrelmail as a nice web interface 
> - basic, but usable ).
>
> Just put the email storage on the drbd mounted drive and you should be 
> ok.
>

drbd is asynchronous replication, isn't it?    so if the active 'master' 
fails just as its written and acknowledged an incoming message, that 
message could be lost if the replication hasn't completed by the time of 
failure ?