Hi all!
First of all, I want ti thank the whole Dovecot community (developers
for developing and fast responses, users for populating and responses
too). Dovecot is a really good and fast IMAP server - it serves near
3000 in our installation.
Now I have a problem and request community's help its resolving;)
Dovecot version: 1.0.13, compiled with vpopmail support.
I have an account [EMAIL PROTECTED] (:-), in which we put all our spam (we
gather statistic later). There can be 10 and more delivery attempts in a
second to maildir of this account during the spam attacks on our server.
The queue of our server can grow up to 20k messages, and all of these
messages are sent to [EMAIL PROTECTED] I found a lot of such strings in
dovecot.log file during such DoS attack:
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:18:48 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX: Timeout
while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:18:59 Info:
msgid=<[EMAIL PROTECTED]>:
save failed to INBOX: Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:20:06 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX: Timeout
while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:20:14 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX:
Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:20:50 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX: Timeout
while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:21:00 Info:
msgid=<[EMAIL PROTECTED]>: save
failed to INBOX: Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:21:01 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX:
Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:22:32 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX:
Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:22:45 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX:
Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:22:45 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX:
Timeout while waiting for lock
dovecot.log:deliver([EMAIL PROTECTED]): May 16 04:23:08 Info:
msgid=<[EMAIL PROTECTED]>: save failed to INBOX: Timeout
while waiting for lock
What can I do for resolving this locks? The queue of my server becomes
really big!
May be, while looking into uidlist file, can dovecot LDA lock it? And
other deliver processes can't open it and wait for him?
$ dovecot --version
1.0.13
# dovecot -n
# 1.0.13: /etc/dovecot.conf
log_path: /var/log/dovecot.log
protocols: imap pop3
ssl_disable: yes
login_dir: /var/run/dovecot/login
login_executable(default): /usr/libexec/dovecot/imap-login
login_executable(imap): /usr/libexec/dovecot/imap-login
login_executable(pop3): /usr/libexec/dovecot/pop3-login
login_greeting: Server is ready.
login_process_per_connection: no
login_greeting_capability(default): yes
login_greeting_capability(imap): yes
login_greeting_capability(pop3): no
login_max_connections: 1024
first_valid_uid: 39
last_valid_uid: 39
first_valid_gid: 39
last_valid_gid: 39
fsync_disable: yes
maildir_copy_with_hardlinks: yes
mail_executable(default): /usr/libexec/dovecot/imap
mail_executable(imap): /usr/libexec/dovecot/imap
mail_executable(pop3): /usr/libexec/dovecot/pop3
mail_plugins(default): quota imap_quota
mail_plugins(imap): quota imap_quota
mail_plugins(pop3): quota
mail_plugin_dir(default): /usr/lib/dovecot/imap
mail_plugin_dir(imap): /usr/lib/dovecot/imap
mail_plugin_dir(pop3): /usr/lib/dovecot/pop3
auth default:
mechanisms: plain login cram-md5
default_realm: tversu.ru
cache_size: 10240
user: vpopmail
username_format: %Lu
passdb:
driver: vpopmail
args: cache_key=%u dovecot
userdb:
driver: vpopmail
socket:
type: listen
client:
path: /var/spool/postfix/private/auth
mode: 438
user: postfix
group: postfix
master:
path: /var/run/dovecot/auth-master
mode: 438
plugin:
quota: maildir:ignore=Trash
---------------------------
WBR, Mike Grozak, TvSU IC
