[Dovecot] dsync backup; compressed to uncompressed

[Michael Smith (DF)]

I need to backup some of the mailboxes on our system.  We are currently using mdbox with zlib compression plugin.

The backups need to be maildir without compression.  How can I accomplish this using dsync?

The following just causes each msg file in maildir to be compressed as well.
dsync -f -u user1 backup maildir:/var/tmp/user1

While this just causes the dsync to fail while spewing a bunch of errors because it can no longer read the compressed mdbox files.
dsync -f -u user1 -o mail_plugins= backup maildir:/var/tmp/user1


# doveconf -n
# 2.2.4: /etc/dovecot/dovecot.conf
# OS: Linux 2.6.32-279.19.1.el6.x86_64 x86_64 CentOS release 6.3 (Final)
auth_debug = yes
auth_debug_passwords = yes
auth_default_realm = domain1.net
auth_master_user_separator = *
auth_mechanisms = plain login
auth_verbose = yes
auth_verbose_passwords = plain
debug_log_path = /var/log/dovecot-debug.log
disable_plaintext_auth = no
dotlock_use_excl = no
lda_mailbox_autocreate = yes
lock_method = dotlock
mail_access_groups = mail
mail_debug = yes
mail_fsync = always
mail_location = mdbox:~/mail:INDEX=~/index
mail_plugins = quota zlib
mail_privileged_group = mail
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
mbox_read_locks = dotlock
mbox_write_locks = dotlock
mdbox_rotate_interval = 1 weeks
mdbox_rotate_size = 20 M
mmap_disable = yes
namespace {
  inbox = yes
  location =
  mailbox Drafts {
    auto = subscribe
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox Sent {
    auto = subscribe
    special_use = \Sent
  }
  mailbox Trash {
    auto = subscribe
    special_use = \Trash
  }
  prefix =
  separator = /
  type = private
}
passdb {
  args = /etc/dovecot/dovecot-sql-master.conf.ext
  driver = sql
  master = yes
  pass = yes
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
plugin {
  autosubscribe = Trash
  autosubscribe2 = Junk
  autosubscribe3 = Drafts
  autosubscribe4 = Sent
  autosubscribe5 = INBOX
  mail_max_userip_connections = 10
  managesieve_max_line_length = 65536
  quota = dict:User quota::file:%h/dovecot.quota
  quota2_rule = Trash:storage=+10%%
  quota3_rule = Junk:storage=+20%%
  quota_rule = *:storage=100M:messages=100000
  recipient_delimiter = +
  sieve_before = /var/opt/mail/global.sieve/
  zlib_save = gz
  zlib_save_level = 9
}
pop3_reuse_xuidl = yes
protocols = imap pop3 sieve lmtp
service auth {
  inet_listener auth {
    port = 113
  }
  unix_listener auth-userdb {
    user = nobody
  }
}
service lmtp {
  inet_listener lmtp {
    port = 24
  }
  process_min_avail = 10
  service_count = 1
}
service managesieve-login {
  inet_listener sieve {
    port = 4190
  }
  process_min_avail = 0
  service_count = 1
  vsz_limit = 64 M
}
ssl = no
ssl_cert = </etc/pki/dovecot/certs/dovecot.pem
ssl_key = </etc/pki/dovecot/private/dovecot.pem
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
protocol lda {
  mail_plugins = quota zlib sieve
}
protocol imap {
  mail_plugins = quota zlib imap_quota
}
protocol sieve {
  mail_max_userip_connections = 10
  mail_plugins = quota zlib
  managesieve_max_line_length = 65536
  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
}
protocol lmtp {
  mail_plugins = quota zlib sieve
}