On Wed, 15 Feb 2012 20:51:59 +0200, Timo Sirainen <t...@iki.fi> wrote: > On 15.2.2012, at 5.08, <l...@airstreamcomm.net> <l...@airstreamcomm.net> > wrote: > >> I know you mentioned you would cover this in a coming post, but we were >> curious what the new dsync replication will be capable of. Would it >> monitor changes to mailboxes and push automatic replication to the remote >> mail store, > > Yes. > >> and if this is the case could it be an N-way replication setup >> in which any host in a cluster can participate in the replication? > > Initially 2-way, but I don't think anything prevents it being N-way. > >> Do you consider this to be a high availability solution? > > > The initial version is really about doing all of this with NFS. In NFS > setup if two replaced storages are both mounted and the primary storage > dies, Dovecot will start using the replica. So that's HA. > > The other possibility is to run Dovecot in two completely separate data > centers and replicate through ssh. Here are more possibilities for how to > do HA, but some of them also have downsides.. dovecot.fi mails are actually > done this way, and can be accessed from either server at any time. I've > been thinking about soon making half of my clients use one server and half > the other one to see if I can find any dsync bugs (I've always 3-4 IMAP > clients connected).
Just to throw our thoughts into the mix, finding an open source multi-site active/active mail solution that does not require building super expensive multi-site storage systems would be a really refreshing way to purse this level of availability. Maybe the only way to accurately get this level of availability is to cluster the storage between sites?