recover form unclean failover

[Michael Menge]

Hi all,

We are testing cyrus 2.4.17 replication in a murder setup.

We try to resolve the scenario of an unclean failover.

In the beginning Server A is the backend and replicates to server B.
In case of failure the backend IP is switched to Server B and the
Server A will restart with the IP of the replica.

If the failover is unclean there will be a rolling replication log file
on Server A.

We have noticed that cyrus catches some problems with split brain.
On the other hand, mailboxes created on server A that are not synced jet
to server B may get lost if the sync_client is started on server B.
Sync_client will send "APPLY UNMAILBOX mailboxname" to the sync_server  
on Server A.

The Article "FastMail storage architecture" on
https://www.fastmail.fm/help/technical/architecture.html indicates that
cyrus is able to recover from split-brain without data loss.

Are there any tools/scripts/recommended steps to fill this gap ;-)
@Bron, how is this scenario handled at fastmail?

Regards

    Michael Menge



--------------------------------------------------------------------------------
M.Menge                                Tel.: (49) 7071/29-70316
Universität Tübingen                   Fax.: (49) 7071/29-5912
Zentrum für Datenverarbeitung          mail:  
michael.menge at zdv.uni-tuebingen.de
Wächterstraße 76
72074 Tübingen
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