Dan Christensen via dovecot wrote:
I should add that these problems arise frequently in practice, even if changes are only being made on a single machine, e.g. laptop1. Flag changes on laptop1 propagate to server, but then are reverted on server when laptop2 syncs with server, and then are reverted on laptop1 when it syncs again with server. If I redo the flag changes on laptop1, the process just repeats and they are removed again.
Suggestions for debugging are very welcome, as currently syncing is much too unreliable for me to continue using it.
Dan
I (and others) have the same issue.
A quote from Stephan Bosch on 20-1-2019:
We're working on it. We have reproduced the problem without difficulty and isolated the commit that caused it.
Tracking internally as DOP-842.
Regards,
Stephan.
Marc
On Feb 16, 2019, Dan Christensen via dovecot <dovecot@dovecot.org> wrote:
I'm running dovecot 2.3.4.1 from https://repo.dovecot.org/ on Ubuntu 18.04 on three machines that I'll call server, laptop1 and laptop2.
Both laptop1 and laptop2 run dovecot sync against server to keep local copies of my imap folders. Even when I initially had only two machines, laptop1 and server, I occasionally noticed that flags were lost, usually custom flags used by Gnus, but I couldn't reliably reproduce the problem.
Now that I have two laptops syncing against the server, the problem has gotten worse and I figured out a way to reproduce it:
- on server: create new IMAP folder test, and put two read messages in it
- on laptop1: doveadm sync -u user -l 10 -m test -f user@server
- on laptop2: doveadm sync -u user -l 10 -m test -f user@server
At this point, all three machines show the two messages M1 and M2 as being read.
- on laptop1: mark message M1 unread
- on laptop2: mark message M2 unread
- on laptop1: doveadm sync -u user -l 10 -m test -f user@server Both laptop1 and server have M1 unread, M2 read, as expected.
- on laptop2: doveadm sync -u user -l 10 -m test -f user@server Now laptop2 and server have M1 *read*, M2 unread.
- on laptop1: doveadm sync -u user -l 10 -m test -f user@server Now laptop1 and the server have both M1 and M2 *read*.
- on laptop2: doveadm sync -u user -l 10 -m test -f user@server Now laptop2 has both read as well.
The two lines that say "*read*" are wrong in my opinion. dsync propagated a read mark to an unread message, even though that message was marked unread more recently than it was marked read.
I usually use stateful sync, and get many related problems. I just did a test in which M1 and M2 started out read, and I started with empty files named dstate.test on laptop1 and laptop2. Then I did the above procedure, using the command
doveadm sync -u user -l 10 -m test -s "
cat dstate.test" user@server > dstate.testAt the end, laptop2 and server had both messages unread (which is good), but laptop1 had only M1 unread, and repeated runs of the sync command did not correct this. So the stateful sync failed to detect a change.
Are these bugs in dovecot? Is there more information that I can provide? The output of doveconf -n on one machine is below, and the others are almost identical.
Thanks for any help!
Dan
# 2.3.4.1 (3c0b8769e): /etc/dovecot/dovecot.conf # OS: Linux 4.15.0-45-generic x86_64 Ubuntu 18.04.1 LTS # Hostname: laptop2 auth_mechanisms = plain login listen = 127.0.0.1 mail_index_log2_max_age = 10 days mail_index_log_rotate_min_age = 1 days mail_index_log_rotate_min_size = 300 k mail_location = maildir:~/Maildir 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 = scheme=CRYPT username_format=%u /etc/dovecot/users driver = passwd-file } protocols = imap service imap-login { inet_listener imap { address = * port = 143 } inet_listener imaps { address = * port = 943 ssl = yes } } service imap { process_limit = 25 } ssl_cert = </etc/dovecot/private/dovecot.pem ssl_client_ca_dir = /etc/ssl/certs ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it userdb { args = username_format=%u /etc/dovecot/users driver = passwd-file } protocol lda { postmaster_address = [elided] } protocol imap { mail_max_userip_connections = 20 }