Good day, everyone.

I'm playing around with replication to create a backup host. I have hosts backend3 (192.168.100.112) and backend3-replica (192.168.100.113). backend3 acts as a mail-receiving host, backend3-replica is a backup for the case of failure.

Both versions are 2.2.13 (form Debian Jessie repository). backend3 receives mail via LMTP-proxy. So far I've managed to setup replication via ssh, but didn't have success with TCP replication. Any help would be much appreciated.

Here is what I have in logs when processing a newly delivered e-mail.

backend3:

Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: none: root=, index=, indexpvt=, control=, inbox=, alt= Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Connect from 192.168.100.101 Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Loading modules from directory: /usr/lib/dovecot/modules Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Module loaded: /usr/lib/dovecot/modules/lib15_notify_plugin.so Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Module loaded: /usr/lib/dovecot/modules/lib20_replication_plugin.so Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: USER#0111#011postmaster@mailnet.local #011service=lmtp#011lip=192.168.100.112#011lport=24#011rip=127.0.0.1#011rport=33133 Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local,127.0.0.1): SELECT pop AS home, uid, gid, CONCAT('*:bytes=', CAST(quota*1024*1024 AS CHAR)) AS quota_ rule FROM users WHERE username = 'postmaster@mailnet.local' Dec 4 17:04:07 backend3 dovecot: auth: Debug: userdb out: USER#0111#011postmaster@mailnet.local #011home=/usr/local/mail/mailnet.local/postmaster#011uid=8#011gid=8#011quota_rule=*:bytes=1048 57600 Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: auth input: postmaster@mailnet.local home=/usr/local/mail/mailnet.local/postmaster uid=8 gid=8 quota_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Added userdb setting: plugin/quota_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Effective uid=8, gid=8, home=/usr/local/mail/mailnet.local/postmaster Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildir:/usr/local/mail/mailnet. local/postmaster/Maildir Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Debug: maildir++: root=/usr/local/mail/mailnet.local/postmaster/Maildir, index=, indexpvt=, control=, inbox=/usr/local/mail/mailnet.local/postma ster/Maildir, alt= Dec 4 17:04:07 backend3 dovecot: lmtp(5451, postmaster@mailnet.local): Debug: Effective uid=8, gid=8, home=/usr/local/mail/mailnet.local/postmaster Dec 4 17:04:07 backend3 dovecot: lmtp(5451, postmaster@mailnet.local): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes location=maildi r:/usr/local/mail/mailnet.local/postmaster/Maildir Dec 4 17:04:07 backend3 dovecot: lmtp(5451, postmaster@mailnet.local): Debug: maildir++: root=/usr/local/mail/mailnet.local/postmaster/Maildir, index=, indexpvt=, control=, inbox=/usr/local /mail/mailnet.local/postmaster/Maildir, alt= Dec 4 17:04:07 backend3 dovecot: lmtp(5451, postmaster@mailnet.local): F0skIVedYVZLFQAAamJeGw: msgid=unspecified: saved mail to INBOX Dec 4 17:04:07 backend3 dovecot: lmtp(5451): Disconnect from 127.0.0.1: Successful quit Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: PASS#0111#011postmaster@mailnet.local#011service=doveadm Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local): query: SELECT username AS user, crypt AS password, proxy_maybe, host FROM users WHERE username = 'postmaster@mailnet.local' AND enabled = 1 Dec 4 17:04:07 backend3 dovecot: auth: Debug: passdb out: PASS#0111#011user=postmaster@mailnet.local#011host=192.168.100.112#011proxy Dec 4 17:04:07 backend3 dovecot: doveadm(postmaster@mailnet.local): Debug: auth input: user=postmaster@mailnet.local host=192.168.100.112 proxy Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: PASS#0111#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.112#011lport=12345#011rip=192.168.100.112#011rport=58217 Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local,192.168.100.112): query: SELECT username AS user, crypt AS password, proxy_maybe, host FROM users WHERE username = 'postmaster@mailnet.local' AND enabled = 1 Dec 4 17:04:07 backend3 dovecot: auth: Debug: passdb out: PASS#0111#011user=postmaster@mailnet.local Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: auth input: user=postmaster@mailnet.local Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: USER#0112#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.112#011lport=12345#011rip=192.168.100.112#011rport=58217 Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local,192.168.100.112): SELECT pop AS home, uid, gid, CONCAT('*:bytes=', CAST(quota*1024*1024 AS CHAR)) AS quota_rule FROM users WHERE username = 'postmaster@mailnet.local' Dec 4 17:04:07 backend3 dovecot: auth: Debug: userdb out: USER#0112#011postmaster@mailnet.local #011home=/usr/local/mail/mailnet.local/postmaster#011uid=8#011gid=8#011quota_rule=*:bytes=1048 57600 Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: auth input: postmaster@mailnet.local home=/usr/local/mail/mailnet.local/postmaster uid=8 gid=8 quo ta_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: Added userdb setting: plugin/quota_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: PASS#0111#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.112#011lport=12345#011rip=192.168.100.113#011rport=43001 Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local,192.168.100.113): query: SELECT username AS user, crypt AS password, proxy_maybe, host FROM users WHE RE username = 'postmaster@mailnet.local' AND enabled = 1 Dec 4 17:04:07 backend3 dovecot: auth: Debug: passdb out: PASS#0111#011user=postmaster@mailnet.local Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: auth input: user=postmaster@mailnet.local Dec 4 17:04:07 backend3 dovecot: auth: Debug: master in: USER#0112#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.112#011lport=12345#011rip=192.168.100.113#011rport=43001 Dec 4 17:04:07 backend3 dovecot: auth-worker(5446): Debug: sql(postmaster@mailnet.local,192.168.100.113): SELECT pop AS home, uid, gid, CONCAT('*:bytes=', CAST(quota*1024*1024 AS CHAR)) AS quota_rule FROM users WHERE username = 'postmaster@mailnet.local' Dec 4 17:04:07 backend3 dovecot: auth: Debug: userdb out: USER#0112#011postmaster@mailnet.local #011home=/usr/local/mail/mailnet.local/postmaster#011uid=8#011gid=8#011quota_rule=*:bytes=1048 57600 Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: auth input: postmaster@mailnet.local home=/usr/local/mail/mailnet.local/postmaster uid=8 gid=8 quo ta_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: Added userdb setting: plugin/quota_rule=*:bytes=104857600 Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: Effective uid=8, gid=8, home=/usr/local/mail/mailnet.local/postmaster Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes lo cation=maildir:/usr/local/mail/mailnet.local/postmaster/Maildir Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.113,postmaster@mailnet.local): Debug: maildir++: root=/usr/local/mail/mailnet.local/postmaster/Maildir, index=, indexpvt=, control=, inb ox=/usr/local/mail/mailnet.local/postmaster/Maildir, alt= Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: Effective uid=8, gid=8, home=/usr/local/mail/mailnet.local/postmaster Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: Namespace inbox: type=private, prefix=, sep=, inbox=yes, hidden=no, list=yes, subscriptions=yes lo cation=maildir:/usr/local/mail/mailnet.local/postmaster/Maildir Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: maildir++: root=/usr/local/mail/mailnet.local/postmaster/Maildir, index=, indexpvt=, control=, inb ox=/usr/local/mail/mailnet.local/postmaster/Maildir, alt= Dec 4 17:04:07 backend3 dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: Namespace : Using permissions from /usr/local/mail/mailnet.local/postmaster/Maildir: mode=0700 gid =default Dec 4 17:04:07 backend3 dovecot: dsync-local(postmaster@mailnet.local): Error: read(backend3-replica.mailnet.local) failed: EOF (version not received) Dec 4 17:04:07 backend3 dovecot: dsync-server(postmaster@mailnet.local): Error: read(192.168.100.113) failed: EOF (version not received)

Here is what goes to backend3-replica's log:

Dec 4 17:04:07 backend3-replica dovecot: auth: Debug: master in: PASS#0111#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.113#011lport=12345#011rip=192.168.100.112#011rport=46266 Dec 4 17:04:07 backend3-replica dovecot: auth-worker(4057): Debug: sql(postmaster@mailnet.local,192.168.100.112): query: SELECT username AS user, crypt AS password, proxy_maybe, host FROM users WHERE username = 'postmaster@mailnet.local' AND enabled = 1 Dec 4 17:04:07 backend3-replica dovecot: auth: Debug: passdb out: PASS#0111#011user=postmaster@mailnet.local#011host=192.168.100.112#011proxy Dec 4 17:04:07 backend3-replica dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: auth input: user=postmaster@mailnet.local host=192.168.100.112 proxy Dec 4 17:04:07 backend3-replica dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Error: doveadm client: Unknown flag: V Dec 4 17:09:07 backend3-replica dovecot: auth: Debug: master in: PASS#0111#011postmaster@mailnet.local #011service=doveadm#011lip=192.168.100.113#011lport=12345#011rip=192.168.100.112#011rport=46269 Dec 4 17:09:07 backend3-replica dovecot: auth-worker(4062): Debug: Loading modules from directory: /usr/lib/dovecot/modules/auth Dec 4 17:09:07 backend3-replica dovecot: auth-worker(4062): Debug: Module loaded: /usr/lib/dovecot/modules/auth/libdriver_mysql.so Dec 4 17:09:07 backend3-replica dovecot: auth-worker(4062): Debug: sql(postmaster@mailnet.local,192.168.100.112): query: SELECT username AS user, crypt AS password, proxy_maybe, host FROM users WHERE username = 'postmaster@mailnet.local' AND enabled = 1 Dec 4 17:09:07 backend3-replica dovecot: auth: Debug: passdb out: PASS#0111#011user=postmaster@mailnet.local#011host=192.168.100.112#011proxy Dec 4 17:09:07 backend3-replica dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Debug: auth input: user=postmaster@mailnet.local host=192.168.100.112 proxy Dec 4 17:09:07 backend3-replica dovecot: doveadm(192.168.100.112,postmaster@mailnet.local): Error: doveadm client: Unknown flag: V

Here is the output of dovecot -n for backend3:

# 2.2.13: /etc/dovecot/dovecot.conf # OS: Linux 3.16.0-4-amd64 x86_64 Debian 8.2 ext4 auth_cache_negative_ttl = 0 auth_cache_size = 100 M auth_cache_ttl = 0 auth_debug = yes auth_mechanisms = plain login auth_verbose = yes disable_plaintext_auth = no doveadm_password = doveadmpass doveadm_port = 12345 first_valid_gid = 8 first_valid_uid = 8 last_valid_gid = 8 last_valid_uid = 8 lda_mailbox_autocreate = yes lmtp_rcpt_check_quota = yes login_trusted_networks = 192.168.100.100/32 192.168.100.101/32 mail_debug = yes mail_gid = 8 mail_location = maildir:/usr/local/mail/%d/%n/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 imap4flags copy include variables body enotify environment mailbox date ihave 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 } mailbox name { auto = subscribe } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql } plugin { mail_replica = tcp:backend3-replica.mailnet.local sieve = ~/.dovecot.sieve sieve_dir = ~/sieve } pop3_client_workarounds = oe-ns-eoh postmaster_address = postmaster@%d protocols = " imap lmtp sieve pop3" service aggregator { fifo_listener replication-notify-fifo { user = mail } unix_listener replication-notify { user = mail } } service doveadm { inet_listener { port = 12345 } } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } process_min_avail = 10 } service lmtp { inet_listener lmtp { port = 24 } } service pop3-login { inet_listener pop3 { port = 110 } inet_listener pop3s { port = 995 ssl = yes } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { mode = 0600 } } ssl = no userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql }

For backend3-replica:

# 2.2.13: /etc/dovecot/dovecot.conf # OS: Linux 3.16.0-4-amd64 x86_64 Debian 8.2 ext4 auth_cache_negative_ttl = 0 auth_cache_size = 100 M auth_cache_ttl = 0 auth_debug = yes auth_mechanisms = plain login auth_verbose = yes disable_plaintext_auth = no doveadm_password = doveadmpass doveadm_port = 12345 first_valid_gid = 8 first_valid_uid = 8 last_valid_gid = 8 last_valid_uid = 8 lda_mailbox_autocreate = yes lmtp_rcpt_check_quota = yes login_trusted_networks = 192.168.100.100/32 192.168.100.101/32 mail_debug = yes mail_gid = 8 mail_location = maildir:/usr/local/mail/%d/%n/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 imap4flags copy include variables body enotify environment mailbox date ihave 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 } mailbox name { auto = subscribe } prefix = } passdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql plugin { mail_replica = tcp:backend3.mailnet.local sieve = ~/.dovecot.sieve sieve_dir = ~/sieve } pop3_client_workarounds = oe-ns-eoh postmaster_address = postmaster@%d protocols = " imap lmtp sieve pop3" service aggregator { fifo_listener replication-notify-fifo { user = mail } unix_listener replication-notify { user = mail } } service doveadm { inet_listener { port = 12345 } } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } process_min_avail = 10 } service lmtp { inet_listener lmtp { port = 24 } } service pop3-login { inet_listener pop3 { port = 110 } inet_listener pop3s { port = 995 ssl = yes } } service replicator { process_min_avail = 1 unix_listener replicator-doveadm { mode = 0600 } } ssl = no userdb { args = /etc/dovecot/dovecot-sql.conf.ext driver = sql }