Master-Master replication question

[William L. Thomson Jr.]

On Monday, July 11, 2016 12:46:50 PM Rick Romero wrote:
>   Quoting "William L. Thomson Jr." <wlt-ml at o-sinc.com>:
> > On Monday, July 11, 2016 10:53:05 AM Rick Romero wrote:
> >> I don't think that'll help.  From what I understand, LMTP is required
> 
> for
> 
> >> replication on delivery.
> > 
> > Where did you come across that requirement? I do not recall that. 
> 
> Hmmm I can't seem to find any reference to it.  Maybe it was from the old
> blog -
> http://blog.dovecot.org/2012/02/dovecot-clustering-with-dsync-based.html 
> My understanding/assumption is that LDA delivers and updates indexes. I
> assume using LMTP delivers, updates indexes and kicks off a quick sync.

That is what I read as well, when others said NFS would not work. I seemed to 
have missed the part you mentioned. Likely skimmed vs read over a cup of 
tea... Maybe that is why I have syncing issues. I will go back and reread. 
Also I could change one end to not be NFS and see if that helps, not sure I 
can do both to really rule that out/in. Likely need to change both to be 100%, 
unless one side being NFS helps show the problem.

> I use qmail as well - that's why I wrote/hacked the LMTP script :)  

That is good to know, I might play around with it in that case. Not to mention 
that there are others still using qmail. With patch for IPv6, not sure I 
really need to replace qmail. I have ASSP in front of qmail, and tends to do 
more of the modern things qmail does not. But thats OT for this list.

> Basically, my last step (if no .qmail exists) is 'pipe to dovecot deliver'
> - I need to change that to 'pipe to this LMTP script' 
> The script allows you to specify a hostname to deliver to, so that you can
> dynamic deliver to the primary server for each user, assuming you're
> already doing that with a director instance.

I do not have a primary server, as I want both to be the same so it does not 
matter which is used, or if either has an issue and goes away. But I might be 
able to achieve the same by setting a primary. Having a primary would likely 
fix most syncing issues, but more with users checking email on the same one its 
arriving on. Other syncing issues might still remain.

> So the theory is.  I've been hitting on pieces of this for years, and I
> want to get all my data replicated before actually I start testing
> again..  The LMTP script is 6 months old and I haven't done anything
> beyond basic testing with it yet :/

I have my replication stuff in production, and for the most part no problems 
short of the delayed emails at times and duplicates at others. If I can run 
the manual command to sync, it will band aid the replication problems.

> If it weren't for all the procmail stuff I've put in over the years I'd
> already be done.  *sigh*

I never got hooked on that, but I do know its quite powerful. I likely need to 
keep and do more server side. I pull most to client and do filter. Though 
procmail can do more than filter.

-- 
William L. Thomson Jr.
Obsidian-Studios, Inc.
http://www.obsidian-studios.com
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