Migrate mailbox from NFS folder to new NFS folder

Hi everyone,

I need to migrate many user mailboxes from an NFS folder to a new NFS folder, both mounted on the same Dovecot server (2.2.27).

Once migrated, users will connect to a new Dovecot server (2.3.4.1).

I would like to know how to use /doveadm backup/ (or sync?) instead of /rsync/ as I noted that after migration with rsync I have duplicates and some e-mails marked as unread.

What is the correct way to achieve this?

Thanks

Cheers