Hi, if you have only one pair of servers, I think replication via dovecot's dsync (or doveadm via ssh) where each server holds all emails as a local storage would be easiest.
There is a caveat with shared folders though. And dovecot replicates only emails. The index is not included, which means for example that you'd need 2 databases for quota - otherwise emails would count twice. Well and any manual index management needs to be done on both sides. https://wiki.dovecot.org/Replication Running a cluster filesystem or NFS as a common base is possible but needs some adjustments of dovecot like turning off caching or memory mapping, which in turn decrease performance. This is only some short handbook knowledge as I haven't implemented replication yet. Greetings Martin Johannes Dauser On Mon, 2018-11-19 at 17:51 -0800, Daniel Miller wrote: > I have a small but critical server that supports our group. As a > single > server - it's obviously a single-point-of-failure for lots of > things. > As I just experienced...again. It was a lot more fun building > systems > from components when I was younger... > > Previously 3rd-party hosted solutions didn't look attractive for > several > reasons...but I'm seeing prices now for cloud virtual machines that > are > stupid cheap. Even if they wind up being limited speed & > availability - > it would seem they'd be a lot better than nothing! > > So I'm considering having at least one backup server for various > services - obviously that includes mail. So now I have to wonder > about > the backend. And while I think I'm reasonably current with > networked > file systems (not distributed or cluster) I haven't played with > replication for a quite a while. > > For this particular usage (I'm envisioning two servers total) - is > there > a need/reason to use any form of networked/distributed/cluster file > storage? Or would this be accomplished via "pure" Dovecot - dsync > replication would keep things updated between the servers and > director > would handle the connections? So with identically configured SMTP > servers, passing to the local LMTP agents, the file system would be > "purely local" with no NFS or other interconnection? >
