Hello,
I have two mail servers and am also experiencing sporadic replication errors over tcps, similar to Reuben. Each server is running Dovecot 2.3.11.3 (502c39af9) on Debian 10.6.
*Log entries from MX1* Nov 18 00:39:26 mx1 dovecot: dsync-local(user@example.com)<Ow3zAjWxtF+TDgAAPHKnuQ>: Error: dsync(mx2.example.com): I/O has stalled, no activity for 600 seconds (last sent=mailbox, last recv=mailbox_state) Nov 18 00:39:26 mx1 dovecot: dsync-local(user@example.com)<Ow3zAjWxtF+TDgAAPHKnuQ>: Error: Timeout during state=sync_mails (send=mailbox recv=mailbox) Nov 18 06:39:32 mx1 dovecot: dsync-local(user@example.com)<6bScGpwFtV+vEQAAPHKnuQ>: Error: dsync(mx2.example.com): I/O has stalled, no activity for 600 seconds (last sent=mailbox, last recv=mailbox_state) Nov 18 06:39:32 mx1 dovecot: dsync-local(user@example.com)<6bScGpwFtV+vEQAAPHKnuQ>: Error: Timeout during state=sync_mails (send=mailbox recv=mailbox) *End*
*Log entries from MX2* Nov 18 00:29:55 mx2 dovecot: dsync-local(user@example.com)<fKK3JzWxtF9zAgAA5XpYKg>: Error: Couldn't lock /var/vmail/user@example.com/.dovecot-sync.lock: fcntl(/var/vmail/user@example.com/.dovecot-sync.lock, write-lock, F_SETLKW) locking failed: Timed out after 30 seconds (WRITE lock held by pid 628) Nov 18 00:34:56 mx2 dovecot: dsync-local(user@example.com)<9IKaB2KytF92AgAA5XpYKg>: Error: Couldn't lock /var/vmail/user@example.com/.dovecot-sync.lock: fcntl(/var/vmail/user@example.com/.dovecot-sync.lock, write-lock, F_SETLKW) locking failed: Timed out after 30 seconds (WRITE lock held by pid 628) Nov 18 00:39:26 mx2 dovecot: doveadm: Error: dsync(mx1.example.com): I/O has stalled, no activity for 600 seconds (last sent=mail_change (EOL), last recv=mailbox) Nov 18 06:39:32 mx2 dovecot: doveadm: Error: dsync(mx1.example.com): I/O has stalled, no activity for 600 seconds (last sent=mail_change (EOL), last recv=mailbox) *End*
I have configured "replication_full_sync_interval = 1 hours", which explains why some of the sync errors occur at the same increment on the hour (if the error does occur).
I've tested replication over tcps using either IPv6 or IPv4 -- this did not appear to make a difference.
Changing replication to occur over tcp solves the issue (with "ssl = yes" commented out, as well).
IMAP clients are primarily connecting to MX1 using SSL, which works well (SSL connections to MX2 also work). These are very low traffic machines at the moment (just 1 user as I continue testing).
I've attached the output of "dovecot -n" from each server.
Are there known bugs with replication using SSL? I'd appreciate any guidance.
Thank you, AP