On Thu, Jan 26, 2012 at 07:05:16PM -0600, Stan Hoeppner wrote: > On 1/26/2012 2:54 PM, Matteo Cazzador wrote: > > Hello, i'va a particular question about mail server. > > Suppose a customer have more than one locations > > in different geographic sites, each one with a mail server with the same > > domain. > > Is it possible to forward every user mail to every locations mail > > servers ? i think it's possible, > > i like to do it with a single node mail server extrernal from locations, > > that forward to every location mail server. > > My customer receive big mail so i don't want to use vpn from locations > > to consult it. > > But i've a problem. > > Is it possibile to consult user mail in one location on specific > > location mail server using imap. > > The difficult is how i can propagate to every mail server action that > > users made. > > Example: if user in location one read mail on server one, i want that in > > server two the same mail result read and not new. > > Is it possible to do so with a specific postfix imap configuration? > > Like an imap cluster? i can't use nfs or virtual disk. > > Thank's a lot > > Postfix is an SMTP server. It has nothing to do with IMAP, and cannot > do what you desire. > > What you seem to be wanting is an active/active IMAP cluster where > changes to mailbox files are reflected immediately on both servers. You > can do this with Dovecot using DRBD and GFS2 over TCP/IP. Be aware this > isn't going to work well for geographically dispersed cluster nodes, > when network latency is high and bandwidth is low, and link reliability > is not ~100%. Depending on the traffic load of these nodes, you may > need a dedicated 10 Mb/s or 100Mb/s link between the two sites. Using > public internet connections for such a cluster setup is not wise. > > Note that this is an engineered solution from the hardware up. You > cannot retrofit such a setup to existing servers. If you are already > using Dovecot please post your question on the Dovecot list. If you are > using Courier or another IMAP server, please ask on the appropriate > mailing list.
You can kind of do it with Cyrus replication as well, which takes out the DRBD layer - but we (Cyrus) strongly recommend an Active/Passive setup rather than Active/Active. IMAP (particularly with CONDSTORE enabled) is not a protocol that's very friendly to the idea of updates happening in multiple locations. The ordering guarantees on changes are very strict about how they're supposed to work. Bron.
