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 the 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
My dovecot.conf:
$ cat /etc/dovecot.conf | grep -v \# | grep -v ^\n
protocols = imap pop3
log_path = /var/log/dovecot.log
ssl_disable = yes
login_user = dovecot
login_process_per_connection = no
login_max_connections = 1024
login_greeting = Server is ready.
>>dotlock_use_excl = yes - can it be the reason?
fsync_disable = yes
first_valid_uid = 39
last_valid_uid = 39
first_valid_gid = 39
last_valid_gid = 39
max_mail_processes = 1024
maildir_copy_with_hardlinks = yes
maildir_copy_preserve_filename = yes
protocol imap {
mail_plugins = quota imap_quota
login_greeting_capability = yes
imap_client_workarounds = outlook-idle
}
protocol pop3 {
pop3_lock_session = no
pop3_uidl_format = %08Xu%08Xv
mail_plugins = quota
}
protocol lda {
postmaster_address = [EMAIL PROTECTED]
mail_plugins = quota cmusieve
sendmail_path = /usr/lib/sendmail
fsync_disable = no
}
auth_cache_size = 10240
auth_username_format = %Lu
auth default {
mechanisms = plain login cram-md5
socket listen {
master {
path = /var/run/dovecot/auth-master
mode = 0666
}
client {
path = /var/spool/postfix/private/auth
mode = 0666
user = postfix
group = postfix
}
}
passdb vpopmail {
args = cache_key=%u dovecot
}
userdb vpopmail {
}
user = vpopmail
ssl_require_client_cert = no
}
dict {
}
plugin {
quota = maildir:ignore=Trash
}
What can I do for resolving this locks?
May be, while looking into uidlist file, can dovecot LDA lock it? And
other deliver processes can't open it and wait for him?
---------------------------
WBR, Mike Grozak, TvSU IC
