Hello Reuben,
I'm having a very similar setup. The 2 main differences: all my users are virtual and the "2nd server" is on a different continent (high latency sync).
Unfortunately the dsync is not working for the moment. Timo is in the process of redesigning it. So once it is release will know about it.
drwx------ 5 lyn lyn 4096 Apr 30 19:32 .INBOX_7a86a62d465a974fb92f00003b258734
First question: why is this random named directory being created in the origin Maildir? Shouldn't the replication be more or less read-only in the origin Maildir?
- the number it is not random, but rather it is the GUID of the folder on the other server. To get rid of this annoying problem you need to clean your source of all these newly created folders, rsync your folders in between the 2 machines, run dsync again (this time it will not mess up with your folder structure)
Second question: If I re-attempt a doveadm sync a second time I get this error:
tornado Maildir # doveadm sync -u lyn remote:root@dustbowl.reub.net dsync-local(lyn): Error: Can't rename mailbox INBOX_7a86a62d465a974fb92f00003b258734 to INBOX: Target mailbox already exists dsync-local(lyn): Error: Can't rename mailbox INBOX to INBOX_eb15f30ea563be4b703200002bd68bb1: Renaming INBOX isn't supported. tornado Maildir #
It's not clear if the second attempt has failed or succeeded, and it's a bit odd that it errors out on a directory that the dovecot sync process itself has created.
do the fix at Q1 and you will not run into this... it is not a permission problem but rather a meta-info problem.
The setup will run fine as long as you only update 1 server and the other one is backup. The current release does not handle well the master-master model (you'll endup with emails like the folders above: duplicated, with GUID appended to them etc etc)...
Wish Timo good luck and inspiration!
Best regards, Andrei