Using dsync for a single mailbox?

[Wim Lewis]

On Tue, 21 Jan 2020, Sami Ketola wrote:
> how does dsync fail? How have you tried? Something like this on the new 
> server:
>
> doveadm -o imapc_server=remote_ip -o imapc_port=remote_port -o imapc_user=<remote_victim> -o imapc_password=<remote_victim_password> backup -u <local_victim> -R imapc:

The best I can do is get it to complete without any errors but without 
transferrig any mail. I've added the imapc config to local.conf,
and I run it like this:

   doveadm -Dv sync -1 -R -u local_user -m mailbox_name imapc:

(or variations on that, e.g. with -n namespace). It successfully logs in 
to the remote imapd, but doesn't decide to transfer anything. If I leave 
off the "-m mailbox_name" it does start traversing the remote maibox 
hierarchy, but I really don't want it to transfer everything --- just some 
specific mailboxes.

One thing that's unclear to me is exactly what strings I should pass to 
the -n and -m flags. Do I specify a namespace by its local prefix, or its 
remote prefix, or its name in the config file, or ... ? And mailbox names?
How does dsync map remote to local names?