Replication to more than one replica?

Roberto R. Morelli morelli at
Mon Aug 13 11:18:04 EDT 2007


In the setup that we are running, we have multiple servers on the West and 
East coast in the USA.  They contain about several hundred accounts (200GB of 
active data) and critical to our 24x7 operations.  I wrote a couple start-up 
scripts to handle the process so that if sync hangs, crashes, or core dumps, 
the imap engine is never touched and can be restarted.  There are a couple 
watchdog apps on the servers to make sure sync is running everywhere.  I am 
always logged into all the replicas to make sure everything is right.

The command used boils down to:

         -r -l -S [hostname of replica #1]"
         -r -l -S [hostname of replica #2]"


--On Friday, August 10, 2007 10:55:31 AM +0200 Per olof Ljungmark 
<peo at> wrote:

> Rob Mueller wrote:
>>> Disagree.  I am replicating one server to two and have been doing it
>>> for quite
>>> a while with cyrus 2.3.
>> Can you explain how you're doing this? If you're just running multiple
>> sync_clients with different config files that point to different replica
>> servers, then what you've got is broken because each sync_client will be
>> randomly grabbing different log files, so each replica will be only
>> getting half the required updates and will at any moment be randomly out
>> of sync with the master.
>> The only way you can reliably make this work is.
>> 1. Write a process that that like sync_client, regularly grabs and
>> atomically rotates the log files in the conf/log directory
>> 2. That process then either:
>> a) puts two copies of the log file in separate directories, and you have
>> two separate sync_client processes running in rolling mode picking up
>> the files in those directories, each sync_client with a different config
>> file pointing to the two different replica servers
>> b) it runs a sync_client -f on the file twice, but with separate config
>> filess to each of the two different replica servers
> Could you do it then with sync_client -S -u instead of -r to one of the
> relicas?
> ----
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