On Sun, Apr 6, 2014 at 2:05 PM, Ramesh <itsrames...@yahoo.co.in> wrote:
> > Hi All, > > Hi! > Presently we have primary MX and backup MX servers, when primary goes down > mails will be queued in secondary MX, once primary restored all messages > pushed from backup MX to primary MX, messages are not lost. I would like to > know any solution sending and receiving messages from backup MX when > primary MX is down? > > Appreciate suggestion, recently due to major internet service down, we are > not able to check mails or send mails. > As Wietse already said, you can just have a replicated message store, as long as you accept that outgoing mail queue (most sites have some messages lying there, waiting to retry) and *maybe* one or two messages in the intermediate queues (highly unlikely) will be "unavailable" until you restore primary, and could be potentially lost if primary dies. Otherwise you would need to replicate queue directories, likely using DRBD. Yes, you can use DRBD over long-distance links, but you will have increased latency and reduced write performance (search for DRBD Proxy for an explanation). I have implemented DRBD using softlayer's private network, but only for systems where reads/writes ratio is high. Ildefonso.
