Hi,

I'm dealing for few days with replication issues between two dovecot containerized instances in Kubernetes environment. After some search, I found this thread that reports exactly the same symptoms I encountered : https://dovecot.org/pipermail/dovecot/2019-October/117353.html I can confirm that downgrade of dovecot to 2.3.7.2 fixes the issue.

Testing usage of -T parameter with a very low value (10s) on 2.3.8 version is reducing perceptible impact of the issue (mails are replicated within the following five minutes).

I'm not expert in dovecot architecture but I tried to put an eye in the code and I'm wondering if this commit is not creating a potential phantom stalled I/O timeout ? https://github.com/dovecot/core/commit/ec817bb2185bb21b34ba6bdd83b32af16dd0b...

In fact, I was unable to see when the counter incremented by io_set_pending is decremented ?

Hoping that this information can help...

Regards. Fabien. +--------+ For technical details : Container images are based on Arch Linux distro image. Here is the configuration of Dovecot server : dovecot -n # 2.3.7.2 (3c910f64b): /etc/dovecot/dovecot.conf # OS: Linux 4.19.66-coreos x86_64 ext4 # Hostname: mailstore-0.mailstore.piafe.svc.cluster.local disable_plaintext_auth = no doveadm_password = # hidden, use -P to show it doveadm_port = 12345 login_greeting = PIAFE Mail Server Ready mail_location = mdbox:/var/mail/%Ld/%Ln mail_plugins = " notify replication quota" namespace inbox { hidden = no inbox = yes list = yes location = mailbox Brouillons { auto = subscribe special_use = \Drafts } mailbox Corbeille { auto = subscribe special_use = \Trash } mailbox "Courrier indésirable" { auto = subscribe special_use = \Junk } mailbox Envoyés { auto = subscribe special_use = \Sent } prefix = separator = / subscriptions = yes type = private } passdb { args = /etc/dovecot/ldap.conf.ext driver = ldap } plugin { mail_replica = tcp:mailstore-1.mailstore.piafe.svc.cluster.local quota = dirsize:User quota quota_grace = 10%% quota_max_mail_size = 20M quota_rule = *:storage=1G quota_rule2 = Trash:storage=+200M quota_status_access = DUNNO quota_status_nouser = DUNNO quota_status_overquota = 552 5.5.2 Mailbox is full } postmaster_address = postmaster@piafe.recouv.fr replication_dsync_parameters = -d -N -l 30 -U -T 10 service aggregator { fifo_listener replication-notify-fifo { user = mailer } unix_listener replication-notify { user = mailer } } service doveadm { inet_listener { port = 12345 } inet_listener http { port = 8080 } } service lmtp { inet_listener lmtp { address = * port = 24 } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { group = mailer mode = 0660 } } ssl = no userdb { args = /etc/dovecot/ldap.conf.ext default_fields = uid=500 gid=500 home=/var/mail/%Ld/%Ln driver = ldap } protocol imap { mail_plugins = " notify replication quota quota" }