Victor Duchovni put forth on 10/28/2010 2:00 PM: > On Thu, Oct 28, 2010 at 11:41:17AM -0700, Peter wrote: > >> I want to use postfix for active/active mode. > > No, you want to cluster your mailstore (IMAP, POP, ...). This is not > Postfix. Multiple Postfix MX hosts do not need to be clustered, the > SMTP design automatically load-balances multiple MX hosts. > > In an HA environment, your front-end SMTP servers would not be where > you store your mail, rather the clustered IMAP servers would be behind > the MX hosts, which are not clustered. > > Designing a clustered mail store is an interesting problem, but really > a Postfix issue.
I think Victor meant "not" a Postfix issue. If you want to build a mail store cluster over a WAN link, start your reading here: http://www.drbd.org http://sourceware.org/cluster/gfs/ The combination of these will allow you to accomplish your cluster goal. Depending on the aggregate write bandwidth of your MTAs and delete b/w of your POPD, you may need a site-to-site link of anywhere from 10Mb/s to 100Mb/s, or maybe even more. If your two servers are located in buildings on the same campus and connected via 100/1000Mb/s ethernet then this solution will work very well. If your two servers are located in two internet colocation facilities and your b/w is limited to 10Mb/s or less, RTTs are unstable, etc, then this solution may not work well for you. Mirroring a disk over a network requires a stable quality network. If your network is stable and the bandwidth sufficient, this is the way you want to cluster across a network. If you lack the network prerequisites, you're not going to be able to effectively implement an active/active cluster with the solution above or any other. -- Stan
