Replication issues master <-> master nfs backend

[Teemu Huovila]

On 22.03.2016 21:30, William L. Thomson Jr. wrote:
> I keep having some replication issues and not sure what can be done to resolve or correct. It 
> does not seem to happen all the time, though for the last ~30 or so minutes and many 
> messages seems to be happening consistent for me.
> 
> I have 2 mail servers, basically clones, and thus master master replication. Most of the time 
> things work fine. But many times an email or several will arrive on one, and never replicate 
> to the other. I am not as concerned on the never replicating, as I am that the user never gets 
> notified.
> 
> Mail arrives on say server 1, users are checking mail on server 2, and they never see the email 
> on server 2. This is not always the case, but its happening enough daily. I then log into one 
> and run sync manually. Which usually syncs the mail on both servers, and then it arrives in 
> the inbox.
> 
> Here is an example, mail is on mail2, but not mail1. I am checking email on mail1 so I am not 
> seeing the 1 email.
> 
> Mail1
> /home/wlt-ml/.maildir/new:
> total 0
> 
> Mail2
> /home/wlt-ml/.maildir/new:
> total 12
> -rw------- 1 wlt-ml site1 8502 Mar 22 14:57 1458673024.7643.mail2
> 
> Then I manually log into mail2 and run this command, though usually I can run it from either 
> side, and just change the name to the other server.
> 
> doveadm sync -u "*" remote:mail1
> 
> And then I end up with the missing email on mail1, and it arrives in my email client shortly 
> there after
> 
> Mail1
> /home/wlt-ml/.maildir/new:
> total 12
> -rw------- 1 wlt-ml site1 8502 Mar 22 14:57 
> 1458673051.M838843P26735.mail1,S=8502,W=8678:2,T
> 
> I have no idea why it does this. It seems to happen when when a full sync has taken place 
> per doveadm replicator status wlt-ml. There does not seem to be any settings to force a full 
> vs fast sync more often. No clue if this is even a full vs fast issue or other.
> 
> I think it tends to happen more when people stay connected to the imap server. I had a 
> theory that closing the email client and opening it again will get dovecot to sync. I believe 
> this is still the case, but not able to confirm 100%. Also users are reporting closing 
> Thunderbird. I can see them logging out and back in in the logs, but email does not replicate 
> or show till I run doveadm sync manually.
> 
> Tempted to have cron invoke that on the regular, but seems very hackish and likely will have 
> its own issues doing that. Since its not the right way or how things were designed. Not sure 
> if this is a bug or what. Hopefully miss-configuration on my end.
You should still include your doveconf -n output. Also any errors and warnings logged by dovecot, could be useful.

br,
Teemu Huovila

 
> Open to any feedback, advice, etc. I can provide replicator configuration but its pretty 
> straight forward and mostly copy/paste from the replication page. Replication works, just 
> seems it is not triggered to replicate at times or something.
> 
> dovecot --version 
> 2.2.22 (fe789d2)
> 
>