I worked out what the problem was

Because I had been planning this move for several months I was syncing home user directories including Maildir for several months

unfortunately I forgot the --delete command to rsync so while users were deleting emails on the original server they were often being copied to the destination server before being deleted.

Therefore there where many more emails in the folder than expected. many quite old.

by resyncing with the --delete command I was able to bring the source and destination into proper sync and all the extra emails were cleaned up

Of course the pop email accounts still had the duplicates I have had to advise the user to clean out there email folders and apologised for the inconvenience.

Chris

On 22/08/2015 5:42 PM, chris wrote:

Hi

I am trying to migrate from a Centos dovecot 1.0.7 install to a debian dovecot 2.1.7 install.

I thought simply replicating the maildirs would be fine (using rsync) but when I fetch mail from the new server using IMAP thunderbird wants to download all the messages again as duplicates.

I searched the wiki over to see if I could find a solution and while it appeared I could use doveadm backup that seems to only work pushing changes from the new server to the old (wrong direction) and that program does not exist on the earlier version of dovecot on the old server.

If I can be very blunt the documentation on the wiki assumes far too much knowledge from the reader. It is often hard to decipher exactly what is meant by many of the obtuse instructions. But that is an aside can anyone give me pointers on how to do this migration for all my users so they don't need to sort through hundreds of duplicated emails?

Chris