Re-starting replication after a long disconnect

[John Krug]

Using Dovecot 2.2.15.8

We use dsync as shown at http://wiki.dovecot.org/Replication <http://wiki.dovecot.org/Replication> to have a second copy of our mail store. Users connect to one server and the other is considered a secondary, and is there “just in case”. If one-way backup/sync would make more sense, I would consider that, but at the time we set it up (October 2013), I recall there was some issue with one-way not being as reliable. 

We had some problems with the secondary mail server and had to take it off line for while. Now that the mail on that server is stale, what is the best way of starting over? When I simply turned it back on after a lengthy break (weeks), some users were reporting deleted messages showing up in their inboxes. I know dsync is master/master and uses index files, but I am not certain of the details and whether this behavior is completely unexpected or not.


The laundry list:
What are the f and R flags for sync? http://wiki2.dovecot.org/Tools/Doveadm/Sync
Use doveadm backup to get the initial data over to the seconday?
Can the server be in use while I do backup?
Do I need to wipe the secondary and start over?


Thanks !
-JK

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John "JK" Krug
System Administrator
The University of Chicago | Laboratory Schools
1362 East 59th Street  |  Chicago, IL  60637
Phone: (773) 834-4476
jk at ucls.uchicago.edu <mailto:jkallo at ucls.uchicago.edu> | http://helpdesk.ucls.uchicago.edu
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