[Dovecot] 2.1.1: doveadm backup errors

[e-frog]

Hello Timo,

I'm experimenting with 'doveadm backup' on 2.1.1 (latest hg, full 
dovecot -n output attached) and haven't managed to get it working.

This is what I have done:
1. Create the directory /tmp/backup which is empty
2. Run  doveadm -v backup -u testuser@ubuntu-test.localdomain 
mdbox:/tmp/backup/

Then I see the following errors:

doveadm -v backup -u testuser@ubuntu-test.localdomain mdbox:/tmp/backup/
dsync(testuser@ubuntu-test.localdomain): Error: Can't delete mailbox 
INBOX: INBOX can't be deleted.
dsync(testuser@ubuntu-test.localdomain): Info: INBOX: only in dest 
(guid=9e4b88178b905f4f456e0000381555a6)
dsync(testuser@ubuntu-test.localdomain): Info: INBOX: only in source 
(guid=bd05451f2fbb574d40600000ec8d17cd)
dsync(testuser@ubuntu-test.localdomain): Error: Trying to open a 
non-listed mailbox with guid=9e4b88178b905f4f456e0000381555a6
dsync(testuser@ubuntu-test.localdomain): Error: msg iteration failed: 
Couldn't open mailbox 9e4b88178b905f4f456e0000381555a6
dsync(testuser@ubuntu-test.localdomain): Error: Trying to open a 
non-listed mailbox with guid=9e4b88178b905f4f456e0000381555a6
dsync(testuser@ubuntu-test.localdomain): Error: Mailbox INBOX changed 
its GUID (bd05451f2fbb574d40600000ec8d17cd -> 
9e4b88178b905f4f456e0000381555a6)
dsync(testuser@ubuntu-test.localdomain): Error: msg iteration failed: 
Couldn't open mailbox bd05451f2fbb574d40600000ec8d17cd
dsync(testuser@ubuntu-test.localdomain): Error: Mailbox INBOX changed 
its GUID (bd05451f2fbb574d40600000ec8d17cd -> 
9e4b88178b905f4f456e0000381555a6)

It somehow finds INBOX in destination however the backup directory is 
newly created and empty.

Thanks,
e-frog
# 2.1.1 (a3b162331cd1): /etc/dovecot/dovecot.conf
# OS: Linux 3.2.0-18-generic-pae i686 Ubuntu precise (development branch)
auth_debug = yes
deliver_log_format = msgid=%m: from=%f: %$
dict {
  dictionary = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes
mail_debug = yes
mail_gid = vmail
mail_home = /home/vmail/%Ld/%Ln
mail_location = mdbox:~/mdbox
mail_plugins = quota virtual fts fts_lucene stats
mail_uid = vmail
mailbox_list_index = yes
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character 
vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy 
include variables body enotify environment mailbox date ihave vnd.dovecot.pipe 
vnd.dovecot.duplicate
namespace {
  hidden = no
  inbox = yes
  list = yes
  location =
  prefix =
  separator = /
  subscriptions = yes
  type = private
}
namespace {
  location = virtual:~/virtual:LAYOUT=maildir++
  prefix = virtual/
  separator = /
  subscriptions = no
  type = private
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
plugin {
  antispam_backend = spool2dir
  antispam_spam = Junk
  antispam_spool2dir_notspam = /home/vmail/learn-ham/%%020lu-%u-%%05luh
  antispam_spool2dir_spam = /home/vmail/learn-spam/%%020lu-%u-%%05lus
  antispam_trash = Trash
  fts = lucene
  fts_lucene = whitespace_chars=@.
  quota = dict:user::proxy::dictionary
  sieve = ~/dovecot.sieve
  sieve_before = /home/vmail/etc/sieve-global/
  sieve_dir = ~/sieve
  sieve_extensions = +vnd.dovecot.pipe +vnd.dovecot.duplicate
  sieve_pipe_bin_dir = /home/vmail/etc/sieve-pipe
  sieve_plugins = sieve_extprograms sieve_duplicate
  stats_refresh = 30 secs
  stats_track_cmds = yes
}
postmaster_address = postmaster@ubuntu-test
protocols = " imap lmtp sieve"
service anvil {
  unix_listener anvil {
    user = vmail
  }
}
service auth {
  client_limit = 4096
  unix_listener /var/spool/postfix/private/dovecot-auth {
    group = postfix
    mode = 0660
    user = postfix
  }
  unix_listener auth-userdb {
    mode = 0600
    user = vmail
  }
}
service config {
  unix_listener config {
    mode = 0600
    user = vmail
  }
}
service dict {
  unix_listener dict {
    mode = 0600
    user = vmail
  }
}
service imap-login {
  inet_listener imaps {
    port = 0
  }
  process_min_avail = 2
  service_count = 0
}
service imap {
  executable = imap postlogin
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postfix
    mode = 0660
    user = postfix
  }
  user = vmail
}
service postlogin {
  executable = script-login rawlog -t /home/vmail/bin/dovecot-postlogin.sh
  user = vmail
}
service stats {
  fifo_listener stats-mail {
    mode = 0600
    user = vmail
  }
  unix_listener stats {
    mode = 0600
    user = vmail
  }
}
ssl = required
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key = </etc/ssl/private/dovecot.pem
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
verbose_proctitle = yes
protocol lmtp {
  mail_plugins = quota virtual fts fts_lucene stats sieve
}
protocol imap {
  imap_client_workarounds = tb-extra-mailbox-sep
  imap_id_log = *
  mail_plugins = quota virtual fts fts_lucene stats imap_quota antispam 
imap_stats
}