[Dovecot] Mailbox with .broken files

[Michael Smith (DF)]

We're using Dovecot 2.2.4 and mdbox storage with compression.

I noticed yesterday that at least one of the accounts has unusual files in it's mail/storage directory.  This account has approximately 17.5G of compressed mail, across about 750 storage files (m.###) using 8G of storage.

Starting on Dec 11, storage files m.409 through m.731 have not only their m.### file, but also a m.###.broken file.  At the same time .temp.<unix time>.<unique id>.<hostname> files also started showing up...
...
-rw--w---- 1 user123 mail     3225 Dec 12 04:38 m.708
-rw--w---- 1 user123 mail   167106 Dec 12 03:35 m.708.broken
-rw--w---- 1 user123 mail    46155 Dec 12 04:38 m.709
-rw--w---- 1 user123 mail   177267 Dec 12 03:40 m.709.broken
-rw--w---- 1 user123 mail 20965889 Nov 26 19:22 m.71
-rw--w---- 1 user123 mail   133248 Dec 12 04:38 m.710
-rw--w---- 1 user123 mail   264361 Dec 12 03:40 m.710.broken
-rw--w---- 1 user123 mail   103407 Dec 12 04:38 m.711
-rw--w---- 1 user123 mail   627736 Dec 12 03:40 m.711.broken
-rw--w---- 1 user123 mail     5132 Dec 12 04:38 m.712
-rw--w---- 1 user123 mail   136244 Dec 12 03:40 m.712.broken
-rw--w---- 1 user123 mail   187224 Dec 12 04:38 m.713
-rw--w---- 1 user123 mail   351104 Dec 12 03:45 m.713.broken
-rw--w---- 1 user123 mail   435793 Dec 12 04:38 m.714
-rw--w---- 1 user123 mail   566906 Dec 12 03:45 m.714.broken
-rw--w---- 1 user123 mail    60916 Dec 12 04:38 m.715
-rw--w---- 1 user123 mail   192028 Dec 12 03:50 m.715.broken
-rw--w---- 1 user123 mail    38051 Dec 12 04:38 m.716
-rw--w---- 1 user123 mail   169163 Dec 12 03:50 m.716.broken
-rw--w---- 1 user123 mail   226067 Dec 12 04:38 m.717
-rw--w---- 1 user123 mail   389948 Dec 12 04:00 m.717.broken
...
-rw--w---- 1 user123 mail 20967506 Dec  2 17:32 m.96
-rw--w---- 1 user123 mail 20967131 Dec  2 18:40 m.97
-rw--w---- 1 user123 mail 20969078 Dec  2 18:38 m.98
-rw--w---- 1 user123 mail 20963978 Dec  2 19:23 m.99
-rw--w---- 1 user123 mail   294968 Dec 11 20:05 .temp.1386813944.P9142Q0M123686.myhost
-rw--w---- 1 user123 mail   294968 Dec 11 20:05 .temp.1386813967.P9213Q0M387733.myhost
-rw--w---- 1 user123 mail   294968 Dec 11 20:05 .temp.1386813970.P9231Q0M371190.myhost
-rw--w---- 1 user123 mail   327736 Dec 11 20:05 .temp.1386813972.P9173Q0M932070.myhost
-rw--w---- 1 user123 mail   327736 Dec 11 20:05 .temp.1386813972.P9239Q0M114754.myhost
-rw--w---- 1 user123 mail   327736 Dec 11 20:05 .temp.1386813983.P9261Q0M640646.myhost
-rw--w---- 1 user123 mail  1048632 Dec 11 20:06 .temp.1386814038.P9515Q0M530600.myhost

I'm not really seeing anything that stands out in the maillog during this time.

What caused this problem?  How concerned should I be about possible lost email?  This is a production environment.

Below is the dovecot -n output.

--
Michael Smith



# dovecot -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 = mydomain.com
auth_master_user_separator = *
auth_mechanisms = plain login
auth_verbose = yes
auth_verbose_passwords = plain
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 =
  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
}