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!