Hello,

We have 3 nodes running, with a two way replication between 2 of them and a 1 way replication to a DR node running off one. We use mdbox, and directors to split traffic across nodes. There is no shared file system.

Users are experiencing messages reappearing in their INBOX as unread with duplicate GUID and message headers. This occurs generally several days after a message was first received (and often actioned; read, moved, trashed, expunged, also often bulk moved/deleted).

We have attempted to remove replication from the equation by cutting down to one single node with all replication disabled which did not have any impact. We have also started regular cache and mailbox purging. There are no logged events when mail items reappear, and we only observe it based on user report, mailbox inspection (doveadm looking for duplicate GUIDs/unique message headers) or seeing IMAP commands being done against the same message twice (e.g. monday they copy to trash, delete and expunge from inbox, delete and expunge from trash, then the next monday they will have to do the same for the reappearing message).

OS: Centos 7

Dovecot: dovecot -version

Scheduled jobs:

*/15 0 * * 0 doveadm sync -u "*" tcps:<dr node>:12345 > /var/log/dovecot/dr_sync.log 2>&1

1 3 * * * doveadm mailbox cache purge -A INBOX

21 3 * * * doveadm mailbox cache purge -A Trash

0 1 * * 0 /usr/bin/doveadm purge -A >/dev/null 2>&1

Conf: dovecot -n

# 2.3.16 (7e2e900c1a): /etc/dovecot/dovecot.conf

# OS: Linux 3.10.0-1160.53.1.el7.x86_64 x86_64 CentOS Linux release 7.9.2009 (Core)

# Hostname: <primary node>

auth_master_user_separator = *

default_vsz_limit = 1 G

disable_plaintext_auth = no

dotlock_use_excl = no

doveadm_password = # hidden, use -P to show it

listen = *

mail_fsync = always

mail_location = mdbox:~/mail

mail_nfs_index = yes

mail_nfs_storage = yes

mail_plugins = " notify replication"

mmap_disable = yes

namespace inbox {

inbox = yes

location =

mailbox Drafts {

special_use = \Drafts

}

mailbox Junk {

special_use = \Junk

}

mailbox Sent {

special_use = \Sent

}

mailbox "Sent Messages" {

special_use = \Sent

}

mailbox Trash {

autoexpunge = 30 days

special_use = \Trash

}

prefix =

separator = .

}

passdb {

args = /etc/dovecot/conf.d/passwd.masterusers

driver = passwd-file

master = yes

}

passdb {

args = /etc/dovecot/conf.d/passwd.masterusers

driver = passwd-file

}

plugin {

mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename save flag_change

mail_log_fields = uid box msgid size flags

mail_log_group_events =

mail_replica = tcps:<second node>:12345

}

protocols = imap

service aggregator {

fifo_listener replication-notify-fifo {

mode = 0666

user = vmail

}

unix_listener replication-notify {

mode = 0666

user = vmail

}

}

service doveadm {

inet_listener {

port = 12345

ssl = yes

}

}

service imap-login {

inet_listener imap {

port = 144

}

inet_listener imaps {

port = 994

ssl = yes

}

}

service replicator {

process_min_avail = 1

unix_listener replicator-doveadm {

mode = 0666

}

}

ssl = required

ssl_cert =

ssl_cipher_list = TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:TLS_AES_128_GCM_SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA

ssl_client_ca_file = /etc/ssl/certs/ca-bundle.crt

ssl_dh = # hidden, use -P to show it

ssl_key = # hidden, use -P to show it

ssl_prefer_server_ciphers = yes

userdb {

args = /etc/dovecot/conf.d/dovecot-dict-auth.conf.ext

driver = dict

}

userdb {

args = /etc/dovecot/conf.d/dovecot-ldap.conf.ext

driver = ldap

}

protocol imap {

mail_max_userip_connections = 9999

mail_plugins = " notify replication mail_log notify"

}

Any thoughts would be greatly appreciated.

Thanks in advance,

Andrew