[Dovecot] Dovecot v2.2 plans

[list at airstreamcomm.net]

On Wed, 15 Feb 2012 20:51:59 +0200, Timo Sirainen <tss at iki.fi> wrote:
> On 15.2.2012, at 5.08, <list at airstreamcomm.net> <list at 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?