<HTML><BODY>Hi!<br><br>Thank you for reply.<br>Users can connect to only one server at a time. I move the master server to another hardware and at this time it is necessary for users to use the mail.<br>If this is not a secure configuration, then can I just run "sync_client -A" from the master server, and then switch users to a replica? <br>After that, swap the roles of master-replica between the servers? I'm right ?<br><br>>We use cyrus aggregator aka cyrus murder, and AFAIK fastmail also uses <br>>multiple<br>>instances on one server with nginx frontends<br><br>Can you give an example of the configuration?<br><br>Best regards.<br><br><blockquote style="border-left:1px solid #0857A6; margin:10px; padding:0 0 0 10px;">
Четверг, 13 сентября 2018, 13:22 +05:00 от Michael Menge <michael.menge@zdv.uni-tuebingen.de>:<br>
<br>
<div id="">
<div class="js-helper js-readmsg-msg">
<style type="text/css"></style>
<div>
<base target="_self" href="https://e.mail.ru/">
<div id="style_15368269530000000447_BODY">Hi,<br>
<br>
This setup is NOT SUPPORTED and WILL BREAK if the replication process <br>
is triggered<br>
from the wrong server (user is active on both servers, user switched <br>
from one server<br>
to the other while the sync-log file is still processed, after split <br>
brain) and<br>
some mailboxes have been subscribed, renamed created deleted.....<br>
<br>
Also there is the risk of a race condition with subscriptions, if a <br>
user subscribes<br>
to multiple folders, the first will trigger a sync from A to B, but as <br>
the folder<br>
is subscribed on B it will trigger a sync from B to A, witch can undo the next<br>
folder subscription.<br>
<br>
These are only some cases that came to my mind. There will be more <br>
cases and it<br>
will be hard to debug. So DON'T DO IT!<br>
<br>
What we do is, that we have distributed our users between multiple<br>
instances, and each server is running one instance as master and one other<br>
as replic. In case of failure or maintenance we stop the master instance, and<br>
promote the corresponding replic and configure them so that they will sync<br>
them back. If the old master is up to date we switch them back.<br>
<br>
We use cyrus aggregator aka cyrus murder, and AFAIK fastmail also uses <br>
multiple<br>
instances on one server with nginx frontends<br>
<br>
Regards,<br>
<br>
Michael<br>
<br>
<br>
<br>
<br>
<br>
Quoting Evgeniy Kononov via Info-cyrus <<a href="mailto:info-cyrus@lists.andrew.cmu.edu">info-cyrus@lists.andrew.cmu.edu</a>>:<br>
<br>
> Sorry! Previous message was sent by mistake.<br>
><br>
> For example, I can configure both servers as follows.<br>
><br>
> Server A.<br>
> -----------------<br>
> /etc/cyrus.conf<br>
> START {<br>
> ...<br>
> syncclient cmd="sync_client -r"<br>
> ...<br>
> }<br>
> SERVICES {<br>
> ...<br>
> syncserver cmd="sync_server" listen="csync"<br>
> ...<br>
> }<br>
><br>
> /etc/imapd.conf<br>
> ...<br>
> sync_host: SERVER-B<br>
> sync_authname: admin<br>
> sync_password: password<br>
> sync_log: 1<br>
> sync_repeat_interval: 30<br>
> sync_timeout: 600<br>
> sync_shutdown_file: /var/lib/imap/syncstop And the same on server B.<br>
> -----------------<br>
> /etc/cyrus.conf<br>
> START {<br>
> ...<br>
> syncclient cmd="sync_client -r"<br>
> ...<br>
> }<br>
> SERVICES {<br>
> ...<br>
> syncserver cmd="sync_server" listen="csync"<br>
> ...<br>
> }<br>
><br>
> /etc/imapd.conf<br>
> ...<br>
> sync_host: SERVER-A<br>
> sync_authname: admin<br>
> sync_password: password<br>
> sync_log: 1<br>
> sync_repeat_interval: 30<br>
> sync_timeout: 600<br>
> sync_shutdown_file: /var/lib/imap/syncstop<br>
> Both server will be as master and as slave in one time.<br>
><br>
> Will there be any problems with this configuration?<br>
> Thank you. --<br>
> Evgeniy Kononov<br>
<br>
<br>
<br>
--------------------------------------------------------------------------------<br>
M.Menge Tel.: (49) 7071/29-70316<br>
Universität Tübingen Fax.: (49) 7071/29-5912<br>
Zentrum für Datenverarbeitung mail: <br>
<a href="mailto:michael.menge@zdv.uni-tuebingen.de">michael.menge@zdv.uni-tuebingen.de</a><br>
Wächterstraße 76<br>
72074 Tübingen<br>
<br>
----<br>
Cyrus Home Page: <a href="http://www.cyrusimap.org/" target="_blank">http://www.cyrusimap.org/</a><br>
List Archives/Info: <a href="http://lists.andrew.cmu.edu/pipermail/info-cyrus/" target="_blank">http://lists.andrew.cmu.edu/pipermail/info-cyrus/</a><br>
To Unsubscribe:<br>
<a href="https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus" target="_blank">https://lists.andrew.cmu.edu/mailman/listinfo/info-cyrus</a></div>
<base target="_self" href="https://e.mail.ru/">
</div>
</div>
</div>
</blockquote>
<br>
<br>-- <br>Evgeniy Kononov<br></BODY></HTML>