[Dovecot] Quota handling on NFS Maildir

[mikkel at euro123.dk]

Hi

Throughout the v. 1.1 betas I have been receiving casual reports that
quota isn't handled correctly (running Maildir).

At the moment I'm running 1.1beta14 but this has been occurring in all
other 1.1 betas as well (I don't know for sure whether this was also an
issue in 1.0, but I think so).
In some earlier betas the issue where worse than is is now (due to
improved NFS locking I guess).


Apparently this occurs when the user shifts between pop3 and IMAP.
maildirsize gets updated whenever mails are coming in, no problems there.

But mails removed aren't always counted as removed - as a result some
users quota keep growing until they reach a limit and e-mails start
getting rejected.

I have been doing some testing and it appears that the updating of the
file maildirsize is sometimes delayed.
I figure this is because Dovecot collects theese changes in the
transactions or index file and then once in a while writes them to
maildirsize.

Could there be a week spot in the code somewhere that allow for this kind
of error when the use of POP3 and IMAP are mixed (I think this happens
even when POP3 and IMAP access aren't concurrent)?

Both my index files and mail storage are located on NFS.


Regards, Mikkel

This is the output of dovecot -n:

# 1.1.beta14: /local/config/dovecot.conf
Warning: fd limit 256 is lower than what Dovecot can use under full load
(more than 768). Either grow the limit or change login_max_processes_count
and max_mail_processes settings
log_path: /local/log/dovecot.run
info_log_path: /local/log/dovecot.run
protocols: imap pop3
ssl_disable: yes
disable_plaintext_auth: no
login_dir: /opt/freeware/dovecot-1.1b14/var/run/dovecot/login
login_executable(default):
/opt/freeware/dovecot-1.1b14/libexec/dovecot/imap-login
login_executable(imap):
/opt/freeware/dovecot-1.1b14/libexec/dovecot/imap-login
login_executable(pop3):
/opt/freeware/dovecot-1.1b14/libexec/dovecot/pop3-login
login_process_per_connection: no
verbose_proctitle: yes
first_valid_uid: 105
first_valid_gid: 105
mmap_disable: yes
mail_nfs_storage: yes
mail_nfs_index: yes
mail_executable(default): /opt/freeware/dovecot-1.1b14/libexec/dovecot/imap
mail_executable(imap): /opt/freeware/dovecot-1.1b14/libexec/dovecot/imap
mail_executable(pop3): /opt/freeware/dovecot-1.1b14/libexec/dovecot/pop3
mail_plugins(default): quota imap_quota trash
mail_plugins(imap): quota imap_quota trash
mail_plugins(pop3): quota
mail_plugin_dir(default): /opt/freeware/dovecot-1.1b14/lib/dovecot/imap
mail_plugin_dir(imap): /opt/freeware/dovecot-1.1b14/lib/dovecot/imap
mail_plugin_dir(pop3): /opt/freeware/dovecot-1.1b14/lib/dovecot/pop3
imap_client_workarounds(default): outlook-idle delay-newmail
tb-extra-mailbox-sep
imap_client_workarounds(imap): outlook-idle delay-newmail
tb-extra-mailbox-sep
imap_client_workarounds(pop3):
pop3_client_workarounds(default):
pop3_client_workarounds(imap):
pop3_client_workarounds(pop3): outlook-no-nuls oe-ns-eoh
auth default:
  mechanisms: plain login digest-md5 cram-md5 apop ntlm
  cache_size: 4096
  cache_ttl: 120
  passdb:
    driver: sql
    args: /local/config/dovecot-sql.conf
  userdb:
    driver: prefetch
  userdb:
    driver: sql
    args: /local/config/dovecot-sql.conf
  socket:
    type: listen
    client:
      path: /var/spool/postfix/private/auth
      mode: 432
      user: postfix
      group: postfix
    master:
      path: /var/run/dovecot/auth-master
      mode: 384
      user: vmail
plugin:
  quota: maildir
  quota_rule2: Trash:storage=10M:messages=100
  trash: /local/config/dovecot-trash.conf