Fwd: Dsync replication - delayed replication (Sync lock)

7 Sep 2020 · *Our setup:*


      Dear Sirs,
Further to my last email have any list members seen this before and are
able to offer advice on how to resolve this please.
I should note as well that we are running Dovecot from the upstream
Debian packages at https://repo.dovecot.org/ce-2.3-latest/debian/buster .
Kind regards
Daniel
-------- Forwarded Message --------
Subject: 	Dsync replication - delayed replication (Sync lock)
Date: 	Tue, 1 Sep 2020 16:17:15 +0100
From: 	Daniel Botting daniel.botting@codethink.co.uk
To: 	dovecot@dovecot.org
Hi,
*Our setup:*
Two Debian 10 machines that are setup to replicate mail between them, we
have round robin DNS setup so a user can connect to either server.
*What should happen:*
Mail is delivered to either server and replicated across straight away
to their mailbox on the other server so it does not matter which one
they are connected to they will receive it fairly soon after delivery.
*What actually happens:*
In some instances the user will experience a delayed receipt of messages
if they are not connected to the server that the message is initially
delivered to, sometimes the delay is 5/10 minutes, we had a recent
support ticket submitted where it was over an hour.
Error message seen in mail.err:
Sep  1 10:16:15 <host name> dovecot:
dsync-local(<username>)<WELSGEERTl8FEAAAZJ7A9A>: Error: Couldn't lock
/path/to/mailbox/.dovecot-sync.lock:
fcntl(/path/to/mailbox/.dovecot-sync.lock, write-lock, F_SETLKW) locking
failed: Timed out after 30 seconds (WRITE lock held by pid 3697)
Process 3697 is dovecot/doveadm-server.
*Doveconf -n output:*
# 2.3.10.1 (a3d0e1171): /etc/dovecot/dovecot.conf
# Pigeonhole version 0.5.10 (67bf5bd7)
# OS: Linux 4.19.0-10-amd64 x86_64 Debian 10.5
# Hostname: <server hostname>
auth_verbose = yes
default_vsz_limit = 0
doveadm_password = # hidden, use -P to show it
first_valid_gid = 8
first_valid_uid = 8
last_valid_gid = 8
last_valid_uid = 8
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes
mail_gid = 8
mail_location = maildir:~/Maildir
mail_plugins = " notify replication"
mail_uid = 8
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope
encoded-character vacation subaddress comparator-i;ascii-numeric
relational regex im
ap4flags copy include variables body enotify environment mailbox date
index ihave duplicate mime foreverypart extracttext editheader imapfla
gs
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 {
special_use = \Trash
}
prefix =
}
passdb {
args = /etc/dovecot/dovecot-ldap.conf.ext
driver = ldap
}
plugin {
mail_replica = tcps:<server being replicated to>:<port being used>
sieve = ~/.dovecot.sieve
sieve_dir = ~/sieve
sieve_extensions = +editheader +imapflags
}
postmaster_address = postmaster@<domain address>
protocols = " imap sieve pop3"
replication_max_conns = 12
service aggregator {
fifo_listener replication-notify-fifo {
user = mail
}
unix_listener replication-notify {
user = mail
}
}
service auth {
unix_listener /var/run/dovecot-exim-bridge {
mode = 0660
user = Debian-exim
}
}
service doveadm {
inet_listener {
port = <port being used for replication>
ssl = yes
}
}
service imap-login {
inet_listener imap {
port = 143
}
}
inet_listener imaps {
port = 993
ssl = yes
}
process_limit = 512
process_min_avail = 4
service_count = 1
}
service imap {
process_limit = 1024
}
service managesieve-login {
inet_listener sieve {
port = <sieve port>
}
process_min_avail = 1
service_count = 8
vsz_limit = 256 M
}
service managesieve {
process_limit = 1024
}
service replicator {
process_min_avail = 1
unix_listener replicator-doveadm {
mode = 0666
}
}
ssl = required
ssl_cert = 
Kind regards
Daniel