doveadm sync backup from old to new server

[Plutocrat]

On 15/05/2020 10.56, Gregory Sloop wrote:
> IMAP sync looks better and better. I'm a little puzzled why I don't just give up walking on the broken glass and use it - but it just bugs the heck out of me.

If you can get the dovecot native sync to work, it seems to be a better option, as it understands all the dovecot index formats etc, and will transfer those correctly. Imapsync doesn't, and when I did that I had a few problems with POP email clients re-downloading their entire Inbox, which produced a few groans. Your mileage may vary. 

Another option for you, if you have the time and energy would be to set up proper replication between the two servers. Then any changes made would be synced in real time, until the cutoff, when you just shut down the old server and the new one is already up to date. But if you can't get a simple sync happening then that might be a bit of over-reach. 

My suspicions on your current situation would center around the complications introduced by docker, and on file/container permissions, environment variables, paths etc. 

How about if you just try a simple doveadm command over ssh from the remote server to make sure that works. eg. from "Sending" server do

ssh root at po.abc.net \
 docker exec b3093cxxxxxx doveadm user user at abc.net

That should execute the doveadm user command on the remote (receiving) server. If that works, then at least you can satisfy yourself that the docker bit is working correctly. Not sure why I'm getting involved in someone else's troubleshooting nightmare! ;-) 

P.