dovecot - Jun 2011 - Performance settings for 500-1000User/per day

hi,

we have 2.0.13 running and most works well, but today we had some minor
problems: The IMAP login process takes sometimes to much time. Over
webmail (Roundcube 0.5.0.3) login wasn't sometimes possible, the normal
clients hasn't any problems, until they login.

We had only ~ 20-30 active accounts, but 50-60 sessions. The most are
Apple products (Ip*/Mac/. ..)because they have 4 sessions or more open.

Also we had ~212 processes with:

dovenull  2065  4364   0 14:50:32 ?           0:00 dovecot/imap-login
vmail  2403  4364   0 14:58:31 ?           0:00 dovecot/imap

So, maybe, it's a miss configuration .... Any suggestions are welcome
for 500-1000User per day.

Our System is a Sun Sunfire X4250 with 16GB memory on Raidz1

Most settings are defaults, so I posting only my changes:

# doveadm -N

# 2.0.13: /usr/local/dovecot/etc/dovecot/dovecot.conf
# OS: SunOS 5.10 i86pc  zfs
auth_cache_negative_ttl = 1 hours
auth_cache_ttl = 1 hours
auth_debug = yes
auth_mechanisms = plain
auth_username_chars
abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
auth_username_format = %Lu
auth_verbose = yes
auth_verbose_passwords = no
base_dir = /var/run/dovecot
debug_log_path = /var/log/dovecot-debug.log
default_login_user = dovenull
default_process_limit = 100
disable_plaintext_auth = no
hostname = hostname.fomain.foo
info_log_path = /var/log/dovecot.log
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = no
lda_original_recipient_header = 
login_greeting = I'm alive
mail_debug = yes
mail_gid = vmail
mail_home = /imap/spool/%d/%1n/%n
mail_location = maildir:/imap/spool/%d/%1n/%n:INDEX=/imap/spool/%
d/indexes/%1n/%n
mail_plugin_dir = /usr/local/dovecot/dovecot2/lib/dovecot/
mail_plugins = acl quota fts fts_squat
mail_privileged_group = vmail
mail_temp_dir = /imap/spool/tmp
mail_uid = vmail
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 imapflags
namespace {
  hidden = no
  inbox = yes
  location = 
  prefix = 
  separator = /
  subscriptions = yes
  type = private
}
namespace {
  inbox = no
  location = maildir:/imap/spool/public
  prefix = public/
  separator = /
  subscriptions = no
  type = public
}
passdb {
  args = /usr/local/dovecot/etc/dovecot/conf.d/dovecot-ldap.conf.ext
  driver = ldap
}
passdb {
  args = scheme=plain-md5 username_format=%
Lu /usr/local/dovecot/etc/dovecot/other-users
  driver = passwd-file
}
plugin {
  acl = vfile:/imap/spool/%d/acl
  autocreate = Sent
  autocreate2 = Drafts
  autocreate3 = Trash
  autocreate4 = Spam
  autosubscribe = Sent
  autosubscribe2 = Drafts
  autosubscribe3 = Trash
  autosubscribe4 = Spam
  fts = squat
  fts_squat = partial=4 full=10
  quota = maildir:User quota
  quota_rule2 = Trash:storage=+10%%
  quota_rule3 = Spam:storage=+20%%
  quota_warning = storage=80%
% /usr/local/dovecot/dovecot2/bin/quota-warning.sh 80
  quota_warning2 = storage=90%
% /usr/local/dovecot/dovecot2/bin/quota-warning.sh 90
  quota_warning3 = storage=95%
% /usr/local/dovecot/dovecot2/bin/quota-warning.sh 95
  sieve = /imap/spool/%d/%1n/%n/sieve/default.sieve
  sieve_dir = /imap/spool/%d/%1n/%n/sieve
  sieve_extensions = +imapflags
  trash = /usr/local/dovecot/etc/dovecot/conf.d/dovecot-trash.conf
}
postmaster_address = postmaster at domain.foo
protocols = imap pop3 lmtp sieve
recipient_delimiter = +
rejection_reason = Your message to <%t> was automatically rejected:%n%r
rejection_subject = Rejected: %s
service auth {
  unix_listener /var/spool/postfix/private/auth {
    group = postdrop
    mode = 0600
    user = postfix
  }
}
service imap-login {
  inet_listener imap {
    port = 143
  }
  inet_listener imaps {
    port = 993
    ssl = yes
  }
  process_min_avail = 8
  vsz_limit = 1 G
}
service lmtp {
  unix_listener /var/spool/postfix/private/dovecot-lmtp {
    group = postdrop
    mode = 0666
    user = postfix
  }
}
service managesieve-login {
  inet_listener sieve {
    port = 4190
  }
  inet_listener sieve_deprecated {
    port = 2001
  }
}
service pop3-login {
  inet_listener pop3 {
    port = 110
  }
  inet_listener pop3s {
    port = 995
    ssl = yes
  }
}
ssl_cert = </usr/local/dovecot/etc/dovecot/ssl/imapd.pem
ssl_key = </usr/local/dovecot/etc/dovecot/ssl/imapd.pem
syslog_facility = mail
userdb {
  args = /usr/local/dovecot/etc/dovecot/conf.d/dovecot-ldap.conf.ext
  driver = ldap
}
userdb {
  args = username_format=%Lu /usr/local/dovecot/etc/dovecot/other-users
  driver = passwd-file
}
verbose_proctitle = yes
verbose_ssl = yes
protocol imap {
  imap_idle_notify_interval = 2 mins
  mail_max_userip_connections = 10
  mail_plugins = acl quota fts fts_squat imap_acl imap_quota mail_log
notify autocreate trash listescape fts fts_squat zlib
  ssl_cert = </usr/local/dovecot/etc-testinstanz/dovecot/ssl/imapd.pem
  ssl_key = </usr/local/dovecot/etc-testinstanz/dovecot/ssl/imapd.pem
}
protocol lda {
  mail_plugins = acl quota fts fts_squat sieve quota fts fts_squat
}
protocol pop3 {
  mail_plugins = acl quota fts fts_squat quota fts fts_squat
  pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
  pop3_reuse_xuidl = yes
  ssl_cert = </usr/local/dovecot/etc-testinstanz/dovecot/ssl/pop3d.pem
  ssl_key = </usr/local/dovecot/etc-testinstanz/dovecot/ssl/pop3d.pem
}
protocol lmtp {
  mail_plugins = acl quota fts fts_squat sieve
}

-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part
URL:
<http://dovecot.org/pipermail/dovecot/attachments/20110620/6d9ebabc/attachment-0002.bin>

hi,

Am 20.06.2011 um 17:51 schrieb Frank Bonnet:
> Did you check the kernel maximum open files option ?
> 
> I had such troubles with a too low limit
I thought, it's only a Linux problem? On the other hand, if so, I would
assume, that I see some log infos, but I saw nothing ...

cu denny

On 6/20/2011 8:16 AM, Denny Schierz wrote:
> hi,
> 
> we have 2.0.13 running and most works well, but today we had some minor
> problems: The IMAP login process takes sometimes to much time. Over
> webmail (Roundcube 0.5.0.3) login wasn't sometimes possible, the normal
> clients hasn't any problems, until they login.
> 
> We had only ~ 20-30 active accounts, but 50-60 sessions. The most are
> Apple products (Ip*/Mac/. ..)because they have 4 sessions or more open.
> 
> Also we had ~212 processes with:
> 
> dovenull  2065  4364   0 14:50:32 ?           0:00 dovecot/imap-login
> vmail  2403  4364   0 14:58:31 ?           0:00 dovecot/imap
> 
> So, maybe, it's a miss configuration .... Any suggestions are welcome
> for 500-1000User per day.
It is customary, and normally required, that one submit server and
client log errors relevant to a problem when posting to a help list.  It
baffles me that some people, in 2011, fail to provide even basic log
information when submitting problem reports.  Without such logging it is
very difficult to help you.

-- 
Stan

On Mon, 2011-06-20 at 15:16 +0200, Denny Schierz wrote:
> we have 2.0.13 running and most works well, but today we had some minor
> problems: The IMAP login process takes sometimes to much time. Over
> webmail (Roundcube 0.5.0.3) login wasn't sometimes possible, the normal
> clients hasn't any problems, until they login.
> 
> We had only ~ 20-30 active accounts, but 50-60 sessions. The most are
> Apple products (Ip*/Mac/. ..)because they have 4 sessions or more open.
> 
> Also we had ~212 processes with:
> 
> dovenull  2065  4364   0 14:50:32 ?           0:00 dovecot/imap-login
> vmail  2403  4364   0 14:58:31 ?           0:00 dovecot/imap
I suppose that means you had 100 IMAP clients simultaneously connected
using SSL, which used up all imap-login processes with default settings.
There should have been a warning logged about it though.

Switch to high performance login process mode
(http://wiki2.dovecot.org/LoginProcess) or increase service imap-login
{ process_limit }.