This is with respect to an error that I am facing in dovecot.

The error is that is seen in logs is "Feb 23 00:04:46 mailblade1 dovecot: IMAP(USERNAME): /indexes/USERNAME/.INBOX/dovecot-uidlist: Duplicate file entry at line 7: 1234776125.M559298P3988.s2o.qlc.co.in,S=13111,W=13470:2, (uid 94277 -> 97805)"

This error is seen for multiple users.

Once this error occurs for a user, the user downloads mails all over again in POP3.

Please help! And let us know what can be done.

Details of our setup

The setup has deployed 2 servers with Dovecot using the same storage over NFS with the following options:

• Dovecot Version: v1.1.8 on both servers
• Server1 for retrieving mails using POP and imap Access
• Server2 for Mail Delivery via postfix and dovecot as LDA
• Number of users: 20000
• Number of mails Handled: 500K per day

--Note: Based on recommendation, kernel was upgraded from 2.6.18 (- see below for details) and yet the issue persists.

Specifications of the server

1. Server spec used for mail Access OS: Linux 2.6.28 i686 CentOS release 5.2 (Final) kernel : 2.6.28 /proc/sys/fs/inotify/max_user_instances = 1024 /proc/sys/fs/epoll/max_user_instances  = 1024 Memory : 2GB

2. Server used for Dovecot Delivery OS: Linux 2.6.21-1.3194.fc7 i686 Fedora release 7 (Moonshine) kernel : 2.6.21 /proc/sys/fs/inotify/max_user_instances = 128 /proc/sys/fs/epoll/max_user_instances  = NA Memory : 2 GB

Conf on both the system as follows =

# 1.1.8: /usr/local/etc/dovecot.conf #NFS Settings mmap_disable: yes mail_nfs_storage: yes mail_nfs_index: yes

#Other special settings pop3_no_flag_updates(pop3): yes pop3_lock_session(pop3): yes

# all the settings base_dir: /usr/local/var/run/dovecot log_path: info_log_path: log_timestamp: %b %d %H:%M:%S syslog_facility: mail protocols: imap pop3 listen(default): *:143 listen(imap): *:143 listen(pop3): *:110 ssl_listen: ssl_disable: yes ssl_ca_file: ssl_cert_file: /etc/ssl/certs/dovecot.pem ssl_key_file: /etc/ssl/private/dovecot.pem ssl_key_password: ssl_parameters_regenerate: 168 ssl_cipher_list: ssl_cert_username_field: commonName ssl_verify_client_cert: no disable_plaintext_auth: no verbose_ssl: no shutdown_clients: yes nfs_check: yes version_ignore: no login_dir: /usr/local/var/run/dovecot/login login_executable(default): /usr/local/libexec/dovecot/imap-login login_executable(imap): /usr/local/libexec/dovecot/imap-login login_executable(pop3): /usr/local/libexec/dovecot/pop3-login login_user: dovecot login_greeting: Welcome to MailServe Popserver. login_log_format_elements: user=<%u> method=%m rip=%r lip=%l %c login_log_format: %$: %s login_process_per_connection: no login_chroot: yes login_greeting_capability: no login_process_size: 64 login_processes_count: 3 login_max_processes_count: 128 login_max_connections: 256 valid_chroot_dirs: mail_chroot: max_mail_processes: 600 mail_max_userip_connections(default): 50 mail_max_userip_connections(imap): 50 mail_max_userip_connections(pop3): 8 verbose_proctitle: yes first_valid_uid: 99 last_valid_uid: 0 first_valid_gid: 99 last_valid_gid: 0 mail_extra_groups: mail_access_groups: mail_privileged_group: mail_uid: mail_gid: mail_location: maildir:~/Maildir:INDEX=/indexes/%u:CONTROL=/indexes/%u mail_cache_fields: mail_never_cache_fields: imap.envelope mail_cache_min_mail_count: 0 mailbox_idle_check_interval: 30 mail_debug: no mail_full_filesystem_access: no mail_max_keyword_length: 50 mail_save_crlf: no mmap_disable: yes dotlock_use_excl: yes fsync_disable: no mail_nfs_storage: yes mail_nfs_index: yes mailbox_list_index_disable: yes lock_method: fcntl maildir_stat_dirs: no maildir_copy_with_hardlinks: yes maildir_copy_preserve_filename: no mbox_read_locks: fcntl mbox_write_locks: dotlock fcntl mbox_lock_timeout: 300 mbox_dotlock_change_timeout: 120 mbox_min_index_size: 0 mbox_dirty_syncs: yes mbox_very_dirty_syncs: no mbox_lazy_writes: yes dbox_rotate_size: 2048 dbox_rotate_min_size: 16 dbox_rotate_days: 1 umask: 63 mail_drop_priv_before_exec: no mail_executable(default): /usr/local/libexec/dovecot/imap mail_executable(imap): /usr/local/libexec/dovecot/imap mail_executable(pop3): /usr/local/libexec/dovecot/pop3 mail_process_size: 256 mail_plugins(default): quota imap_quota mail_plugins(imap): quota imap_quota mail_plugins(pop3): quota mail_plugin_dir(default): /usr/local/lib/dovecot/imap mail_plugin_dir(imap): /usr/local/lib/dovecot/imap mail_plugin_dir(pop3): /usr/local/lib/dovecot/pop3 mail_log_prefix: %Us(%u): mail_log_max_lines_per_sec: 10 imap_max_line_length: 65536 imap_capability: imap_client_workarounds: imap_logout_format: bytes=%i/%o pop3_no_flag_updates(default): no pop3_no_flag_updates(imap): no pop3_no_flag_updates(pop3): yes pop3_enable_last: no pop3_reuse_xuidl: no pop3_lock_session(default): no pop3_lock_session(imap): no pop3_lock_session(pop3): yes pop3_uidl_format: %08Xu%08Xv pop3_client_workarounds(default): pop3_client_workarounds(imap): pop3_client_workarounds(pop3): outlook-no-nuls pop3_logout_format: top=%t/%p, retr=%r/%b, del=%d/%m, size=%s dict_db_config: auth default: mechanisms: plain realms: default_realm: cache_size: 0 cache_ttl: 3600 cache_negative_ttl: 3600 executable: /usr/local/libexec/dovecot/dovecot-auth user: root chroot: username_chars: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890.-_@ username_translation: username_format: master_user_separator: anonymous_username: anonymous krb5_keytab: gssapi_hostname: winbind_helper_path: /usr/bin/ntlm_auth failure_delay: 2 verbose: no debug: no debug_passwords: no ssl_require_client_cert: no ssl_username_from_cert: no ntlm_use_winbind: no count: 1 worker_max_count: 5 worker_max_request_count: 0 process_size: 256 passdb: driver: sql args: /usr/local/etc/dovecot-mysql.conf deny: no pass: no master: no userdb: driver: sql args: /usr/local/etc/dovecot-mysql.conf userdb: driver: prefetch args: socket: type: listen client: path: /var/run/dovecot/auth-client mode: 432 user: nobody group: nobody master: path: /var/run/dovecot/auth-master mode: 384 user: nobody group: nobody plugin: quota: maildir:storage=1024