[Dovecot] Dot Lock timestmap, users disconnections from roundcube

[Maria Arrea]

Hello.

 We are running dovecot 2.0.13 with mdbox+zlib on RHEL 5.7 x64, ext4. We use NTP. Indexes are in a iSCSI raid 10, mailboxes in raid5. No NFS. We have detected that sometimes all users get disconnected from roundcube at the same time. In dovecot logs we hundreds of lines like this:

 Nov 3 09:23:07 buzon dovecot: imap(mcrivero at mydomain): Warning: Created dotlock file's timestamp is different than current time (1320308587 vs 1320308542): /buzones/mydomain/03/67/mcrivero/subscriptions
 Nov 3 09:23:07 buzon dovecot: imap(mcrivero at mydomain): Connection closed bytes=0/295
 Nov 3 09:23:07 buzon dovecot: imap(delolmo at mydomain): Warning: Created dotlock file's timestamp is different than current time (1320308587 vs 1320308542): /buzones/mydomain/15/77/delolmo/subscriptions
 Nov 3 09:23:07 buzon dovecot: imap(delolmo at mydomain): Connection closed bytes=0/295



 I have been googling but I only see problems with remote NFS, our setup does not use NFS. I give you doveconf -n output & mount options, if more info es needed, please ask.

 doveconf -n output


 # 2.0.13: /etc/dovecot/dovecot.conf
 # OS: Linux 2.6.18-274.el5 x86_64 Red Hat Enterprise Linux Server release 5.7 (Tikanga) ext4
 auth_cache_negative_ttl = 10 secs
 auth_cache_size = 10 M
 auth_cache_ttl = 2 mins
 auth_master_user_separator = *
 auth_mechanisms = plain login
 auth_worker_max_count = 3500
 base_dir = /var/run/dovecot/
 default_client_limit = 5000
 default_process_limit = 6500
 disable_plaintext_auth = no
 imap_client_workarounds = tb-extra-mailbox-sep delay-newmail tb-lsub-flags
 lda_mailbox_autocreate = yes
 lda_mailbox_autosubscribe = yes
 mail_fsync = never
 mail_gid = entrega
 mail_home = /buzones/mydomain/%2.26Hn/%2.200Hn/%n/home_usuario/
 mail_location = mdbox:/buzones/mydomain/%2.26Hn/%2.200Hn/%n:INDEX=/indices_dovecot/indices/%2.26Hn/%2.200Hn/%n
 mail_max_userip_connections = 15000
 mail_plugins = " zlib acl quota autocreate"
 mail_uid = entrega
 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
 mdbox_rotate_interval = 1 days
 mdbox_rotate_size = 60 M
 passdb {
 args = /etc/dovecot/dovecot-ldap.conf
 driver = ldap
 }
 passdb {
 args = /etc/usuario_maestro.txt
 driver = passwd-file
 master = yes
 }
 passdb {
 args = /etc/dovecot/dovecot-ldap.conf
 driver = ldap
 }
 plugin {
 acl = vfile
 autocreate = SPAM
 autocreate2 = Sent
 autocreate3 = Drafts
 autocreate4 = Trash
 autosubscribe = SPAM
 autosubscribe2 = Sent
 autosubscribe3 = Drafts
 autosubscribe4 = Trash
 lda_mailbox_autosubscribe = yes
 quota = dict:Cuota de usuario::file:/buzones/cuotas/%n
 quota_rule2 = Trash:storage=+10%%
 quota_warning = storage=90%% aviso_cuota 90 %u
 sieve = /buzones/mydomain/%2.26Hn/%2.200Hn/%n/home_usuario/dovecot.sieve
 sieve_dir = /buzones/mydomain/%2.26Hn/%2.200Hn/%n/home_usuario/sieve/
 zlib_save = gz
 zlib_save_level = 9
 }
 pop3_no_flag_updates = yes
 protocols = pop3 imap sieve
 service anvil {
 client_limit = 25000
 }
 service auth {
 client_limit = 28000
 unix_listener auth-master {
 user = entrega
 }
 unix_listener auth-userdb {
 user = entrega
 }
 user = root
 }
 service aviso_cuota {
 executable = script /usr/local/bin/quota-warning.sh
 unix_listener aviso_cuota {
 mode = 0666
 }
 user = entrega
 }
 service imap-login {
 executable = /usr/libexec/dovecot/imap-login
 group = dovenull
 service_count = 0
 }
 service imap {
 executable = /usr/libexec/dovecot/imap
 process_limit = 6000
 }
 service managesieve-login {
 executable = /usr/libexec/dovecot/managesieve-login
 inet_listener sieve {
 port = 2000
 }
 process_limit = 2000
 }
 service managesieve {
 executable = /usr/libexec/dovecot/managesieve
 process_limit = 5000
 }
 service pop3-login {
 executable = /usr/libexec/dovecot/pop3-login
 process_limit = 4000
 service_count = 0
 }
 service pop3 {
 executable = /usr/libexec/dovecot/pop3
 process_limit = 4000
 }
 ssl_ca = </etc/pki/generico/cacert.crt.pem
 ssl_cert = </etc/pki/generico/wildcard-us_es.crt
 ssl_key = </etc/pki/generico/wildcard-key.pem
 userdb {
 args = /etc/dovecot/dovecot-ldap.conf
 driver = ldap
 }
 userdb {
 args = /etc/dovecot/dovecot-ldap-userdb.conf
 driver = ldap
 }
 verbose_proctitle = yes
 protocol sieve {
 managesieve_implementation_string = dovecot
 managesieve_logout_format = bytes=%i/%o
 managesieve_max_line_length = 65536
 }
 protocol lda {
 hostname = mydomain
 info_log_path =
 log_path =
 mail_fsync = optimized
 mail_plugins = sieve zlib quota
 postmaster_address = evcorreo at mydomain
 syslog_facility = mail
 }
 protocol imap {
 mail_plugins = zlib autocreate quota imap_quota
 }
 protocol pop3 {
 mail_plugins = zlib
 pop3_enable_last = yes
 pop3_uidl_format = %g
 }

 mount points:

 /dev/mapper/Volumen_0-Logico_0 on / type ext3 (rw)
 proc on /proc type proc (rw)
 sysfs on /sys type sysfs (rw)
 devpts on /dev/pts type devpts (rw,gid=5,mode=620)
 /dev/sda1 on /boot type ext3 (rw)
 tmpfs on /dev/shm type tmpfs (rw)
 none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
 sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
 /dev/mapper/Buzon_mydomain-buzones on /buzones type ext4 (rw,noatime,nodiratime,nobarrier,commit=15,data=writeback)

 Indexes are located somewhere in "/" mount point.