[Dovecot] Dovecot clustering with dsync-based replication

[Charles Marcus]

On 2012-02-28 9:43 AM, Timo Sirainen <tss at iki.fi> wrote:
> On Tue, 2012-02-28 at 09:27 -0500, Charles Marcus wrote:
>> On 2012-02-28 9:03 AM, Timo Sirainen<tss at iki.fi>  wrote:
>>> This document describes a design for a dsync-replicated Dovecot cluster.
>>
>> <snip>
>>
>> Wow, talk about timing... this looks like a perfect answer to my
>> previous question about setting up two servers in two different
>> locations to serve two different sets of users locally...

> Yeah, I was delaying answering it until I posted this.

Cool, thanks - I look forward to any comments you might have on my 
current plan.

>> Looks like it wouldn't really matter which server they connected to
>> externally, as any changes would simply be replicated.

> Well, preferably users would connect to the same server. If both servers
> have done changes at the same time, there can be some temporary
> (possibly user-visible) confusion.

Point taken - and thinking about it, the amount of traffic would be 
negligible, since users accessing emails remotely is much less than 
internally.

But a question out of curiosity: can the Director be configured to 
redirect userA to private IP #.#.#.# when connecting from a local 
subnet, but connect them to Public IP ##.##.##.##.## when accessing 
remotely? I don't know enough about routing to answer this myself... but 
if it is possible, then I could minimize traffic on  the inter-office 
link - but there really is not enough remote traffic to worry about this 
too much I think.

>> Timo, state above that this 'describes a design'... does this mean that
>> this is doable right now? Which of the following terms would you use to
>> describe it at this point in time?
>>
>> Potentially problematic

> Not finished yet, so closest to this. :) I'm planning on making our own
> mails use this within a few weeks (currently it's a dsync in crontab
> every 5 minutes).

Cool, it sounds like it may be safe to set this up then in say 2 or 3 
months? Since I'll most likely be contracting with your company to help 
with this, I'll wait and see what you say once we're ready to roll this 
out - and maybe you'll be willing to give us a deal on the 
implementation and/or support costs if we're willing to serve as guinea 
pigs. ;)

Thanks!

-- 

Best regards,

Charles