Very high load

Thu Sep 21 00:56:17 EEST 2017

Hi,

I am using dovecot 2.0.9 (official CentOS rpm), I am experiencing very high load issue.

I think it is something related to my storage (/var/spool is about 3 TB and it is almost full).

I noticed those kind of messages in /var/log/maillog:

Warning: Maildir: Scanning /var/spool/pop/domains/domain.it/username/Maildir/cur took 100 seconds (14281 readdir()s, 0 rename()s to cur/)

Warning: Maildir /var/spool/pop/domains/domain.it/username/Maildir: Synchronization took 103 seconds (0 new msgs, 0 flag change attempts, 0 expunge attempts)

I wondering if there is something to try, at configuration level, to "mitigate" this..

I use Maildir format, MTA is postfix, I have many users (> 10000) with pop3/imap/webmail access. Physical server with 8 GB RAM and two CPU (Intel(R) Pentium(R) D CPU 3.00GHz)

This is my dovecot's conf:

auth_anonymous_username = anonymous
auth_cache_negative_ttl = 1 hours
auth_cache_size = 0
auth_cache_ttl = 1 hours
auth_debug = no
auth_debug_passwords = no
auth_default_realm =
auth_failure_delay = 2 secs
auth_first_valid_uid = 500
auth_gssapi_hostname =
auth_krb5_keytab =
auth_last_valid_uid = 0
auth_master_user_separator =
auth_mechanisms = plain login digest-md5 cram-md5
auth_realms =
auth_socket_path = auth-userdb
auth_ssl_require_client_cert = no
auth_ssl_username_from_cert = no
auth_use_winbind = no
auth_username_chars = abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@
auth_username_format =
auth_username_translation =
auth_verbose = no
auth_verbose_passwords = no
auth_winbind_helper_path = /usr/bin/ntlm_auth
auth_worker_max_count = 30
base_dir = /var/run/dovecot
config_cache_size = 1 M
debug_log_path = /var/log/dovecot.log
default_client_limit = 1000
default_idle_kill = 60
default_internal_user = dovecot
default_login_user = dovenull
default_process_limit = 100
default_vsz_limit = 256 M
deliver_log_format = msgid=%m: %$
dict_db_config =
director_doveadm_port = 0
director_mail_servers =
director_servers =
director_user_expire = 15 mins
disable_plaintext_auth = no
dotlock_use_excl = no
doveadm_socket_path = doveadm-server
doveadm_worker_count = 0
first_valid_gid = 89
first_valid_uid = 89
hostname =
imap_capability =
imap_client_workarounds =
imap_id_log =
imap_id_send =
imap_idle_notify_interval = 2 mins
imap_logout_format = bytes=%i/%o
imap_max_line_length = 64 k
info_log_path =
last_valid_gid = 0
last_valid_uid = 0
lda_mailbox_autocreate = no
lda_mailbox_autosubscribe = no
lda_original_recipient_header =
libexec_dir = /usr/libexec/dovecot
listen = *, ::
lmtp_proxy = no
lmtp_save_to_detail_mailbox = no
lock_method = fcntl
log_path = syslog
log_timestamp = "%b %d %H:%M:%S "
login_access_sockets =
login_greeting = Dovecot ready.
login_log_format = %$: %s
login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e %c
login_trusted_networks =
mail_access_groups =
mail_attachment_dir =
mail_attachment_fs = sis posix
mail_attachment_hash = %{sha1}
mail_attachment_min_size = 128 k
mail_cache_fields = flags
mail_cache_min_mail_count = 0
mail_chroot =
mail_debug = no
mail_fsync = optimized
mail_full_filesystem_access = no
mail_gid = 89
mail_home =
mail_location = maildir:/coraid-s2l2/domains
mail_log_prefix = "%s(%u): "
mail_max_keyword_length = 50
mail_max_lock_timeout = 0
mail_max_userip_connections = 10
mail_never_cache_fields = imap.envelope
mail_nfs_index = no
mail_nfs_storage = no
mail_plugin_dir = /usr/lib64/dovecot
mail_plugins =
mail_privileged_group =
mail_save_crlf = no
mail_temp_dir = /tmp
mail_uid = 89
mailbox_idle_check_interval = 30 secs
mailbox_list_index_disable = no
maildir_copy_with_hardlinks = yes
maildir_stat_dirs = no
maildir_very_dirty_syncs = no
managesieve_client_workarounds =
managesieve_implementation_string = Dovecot Pigeonhole
managesieve_logout_format = bytes=%i/%o
managesieve_max_compile_errors = 5
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 imapflags notify
master_user_separator =
mbox_dirty_syncs = yes
mbox_dotlock_change_timeout = 2 mins
mbox_lazy_writes = yes
mbox_lock_timeout = 5 mins
mbox_min_index_size = 0
mbox_read_locks = fcntl
mbox_very_dirty_syncs = no
mbox_write_locks = fcntl
mdbox_preallocate_space = no
mdbox_rotate_interval = 0
mdbox_rotate_size = 2 M
mmap_disable = no
namespace {
hidden = no
inbox = yes
list = yes
location =
prefix = INBOX.
separator = .
subscriptions = yes
type = private
}
passdb {
args = /etc/dovecot/dovecot-sql.conf.ext
deny = no
driver = sql
master = no
pass = no
}
passdb {
args = /etc/dovecot/dovecot-sql-crypt.conf.ext
deny = no
driver = sql
master = no
pass = no
}
plugin {
sieve = ~/.dovecot.sieve
sieve_dir = ~/sieve
sieve_extensions = +notify +imapflags
sieve_max_script_size = 1M
}
pop3_client_workarounds =
pop3_enable_last = no
pop3_fast_size_lookups = no
pop3_lock_session = no
pop3_logout_format = top=%t/%p, retr=%r/%b, del=%d/%m, size=%s
pop3_no_flag_updates = no
pop3_reuse_xuidl = no
pop3_save_uidl = no
pop3_uidl_format = %08Xu%08Xv
postmaster_address =
protocols = imap pop3 lmtp sieve
quota_full_tempfail = no
recipient_delimiter = +
rejection_reason = Your message to <%t> was automatically rejected:%n%r
rejection_subject = Rejected: %s
sendmail_path = /usr/sbin/sendmail
service anvil {
chroot = empty
client_limit = 0
drop_priv_before_exec = no
executable = anvil
extra_groups =
group =
idle_kill = 4294967295 secs
privileged_group =
process_limit = 1
process_min_avail = 1
protocol =
service_count = 0
type = anvil
unix_listener anvil-auth-penalty {
group =
mode = 0600
user =
}
unix_listener anvil {
group =
mode = 0600
user =
}
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
service auth-worker {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = auth -w
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 1
type =
unix_listener auth-worker {
group =
mode = 0600
user = $default_internal_user
}
user =
vsz_limit = 18446744073709551615 B
}
service auth {
chroot =
client_limit = 4096
drop_priv_before_exec = no
executable = auth
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 1
process_min_avail = 0
protocol =
service_count = 0
type =
unix_listener auth-client {
group =
mode = 0600
user =
}
unix_listener auth-login {
group =
mode = 0600
user = $default_internal_user
}
unix_listener auth-master {
group =
mode = 0600
user =
}
unix_listener auth-userdb {
group =
mode = 0600
user =
}
unix_listener login/login {
group =
mode = 0666
user =
}
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
service config {
chroot =
client_limit = 0
drop_priv_before_exec = no
executable = config
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 0
type = config
unix_listener config {
group =
mode = 0600
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service dict {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = dict
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 0
type =
unix_listener dict {
group =
mode = 0600
user =
}
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
service director {
chroot =
client_limit = 0
drop_priv_before_exec = no
executable = director
extra_groups =
fifo_listener login/proxy-notify {
group =
mode = 00
user =
}
group =
idle_kill = 4294967295 secs
inet_listener {
address =
port = 0
ssl = no
}
privileged_group =
process_limit = 1
process_min_avail = 0
protocol =
service_count = 0
type =
unix_listener director-admin {
group =
mode = 0600
user =
}
unix_listener director-userdb {
group =
mode = 0600
user =
}
unix_listener login/director {
group =
mode = 00
user =
}
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
service dns_client {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = dns-client
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 0
type =
unix_listener dns-client {
group =
mode = 0666
user =
}
unix_listener login/dns-client {
group =
mode = 0666
user =
}
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
service doveadm {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = doveadm-server
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 1
type =
unix_listener doveadm-server {
group =
mode = 0600
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service imap-login {
chroot = login
client_limit = 0
drop_priv_before_exec = no
executable = imap-login
extra_groups =
group =
idle_kill = 0
inet_listener imap {
address =
port = 143
ssl = no
}
inet_listener imaps {
address =
port = 993
ssl = yes
}
privileged_group =
process_limit = 0
process_min_avail = 0
protocol = imap
service_count = 1
type = login
user = $default_login_user
vsz_limit = 64 M
}
service imap {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = imap
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 1024
process_min_avail = 0
protocol = imap
service_count = 1
type =
unix_listener login/imap {
group =
mode = 0666
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service lmtp {
chroot =
client_limit = 0
drop_priv_before_exec = no
executable = lmtp
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol = lmtp
service_count = 0
type =
unix_listener lmtp {
group =
mode = 0666
user =
}
user =
vsz_limit = 0
}
service log {
chroot =
client_limit = 0
drop_priv_before_exec = no
executable = log
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 1
process_min_avail = 0
protocol =
service_count = 0
type = log
user =
vsz_limit = 18446744073709551615 B
}
service managesieve-login {
chroot = login
client_limit = 0
drop_priv_before_exec = no
executable = managesieve-login
extra_groups =
group =
idle_kill = 0
inet_listener sieve {
address =
port = 4190
ssl = no
}
privileged_group =
process_limit = 0
process_min_avail = 0
protocol = sieve
service_count = 1
type = login
user = $default_login_user
vsz_limit = 64 M
}
service managesieve {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = managesieve
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol = sieve
service_count = 1
type =
unix_listener login/sieve {
group =
mode = 0666
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service pop3-login {
chroot = login
client_limit = 0
drop_priv_before_exec = no
executable = pop3-login
extra_groups =
group =
idle_kill = 0
inet_listener pop3 {
address =
port = 110
ssl = no
}
inet_listener pop3s {
address =
port = 995
ssl = yes
}
privileged_group =
process_limit = 0
process_min_avail = 0
protocol = pop3
service_count = 1
type = login
user = $default_login_user
vsz_limit = 64 M
}
service pop3 {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = pop3
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 1024
process_min_avail = 0
protocol = pop3
service_count = 1
type =
unix_listener login/pop3 {
group =
mode = 0666
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service ssl-params {
chroot =
client_limit = 0
drop_priv_before_exec = no
executable = ssl-params
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 0
type = startup
unix_listener login/ssl-params {
group =
mode = 0666
user =
}
unix_listener ssl-params {
group =
mode = 0666
user =
}
user =
vsz_limit = 18446744073709551615 B
}
service tcpwrap {
chroot =
client_limit = 1
drop_priv_before_exec = no
executable = tcpwrap
extra_groups =
group =
idle_kill = 0
privileged_group =
process_limit = 0
process_min_avail = 0
protocol =
service_count = 0
type =
user = $default_internal_user
vsz_limit = 18446744073709551615 B
}
shutdown_clients = yes
ssl = yes
ssl_ca =
ssl_cert = </etc/nginx/ssl/wildcard.domain.net_bundle.crt
ssl_cert_username_field = commonName
ssl_cipher_list = ALL:!LOW:!SSLv2:!EXP:!aNULL
ssl_dh_parameters_length = 1024
ssl_key = </etc/nginx/ssl/wildcard.domain.net.key
ssl_key_password =
ssl_parameters_file = ssl-parameters.dat
ssl_parameters_regenerate = 0
ssl_protocols = !SSLv2 !SSLv3
ssl_verify_client_cert = no
syslog_facility = mail
userdb {
args = /etc/dovecot/dovecot-sql.conf.ext
driver = sql
}
valid_chroot_dirs =
verbose_auth = no
verbose_proctitle = no
verbose_ssl = no
version_ignore = no
protocol lmtp {
mail_plugins =
}
protocol lda {
mail_plugins =
}
protocol imap {
imap_id_log = *
}

Thank you!