Replication and failover

Nik Conwell nik at
Thu May 10 12:14:44 EDT 2007

On Jan 18, 2007, at 5:35 PM, Rob Mueller wrote:

>> Attached is our operation group's notes on the subject.  It makes
>> reference to the tool we use to manage the OS of the machines
>> (radmind), but it should be pretty clear what they are talking about
>> without any radmind knowledge.
> As an FYI, we have a similar procedure to this, the main  
> differences are:
> 1. We don't change the DNS. Instead we give each machine a primary  
> IP address, but we also create IP addresses for "cyrusXmaster" and  
> "cyrusXreplica" names(where X is numbers for each machine). When we  
> swap roles, we rebind the different IPs to the particular machines  
> and send ARPs to clear the router table, rather than changing the  
> DNS. This means you can always access the master as "cyrusXmaster"  
> from every machine without having to worry about DNS getting out of  
> sync.
> 2. Every machine has cyrus-master.conf, cyrus-replica.conf, imapd- 
> master.conf and imapd-replica.conf. We just symlink cyrus.conf and  
> imapd.conf to the appropriate file depending on what mode the  
> machine is currently in

Do you have separate IP addresses for each instance of cyrus on the  
machine as well, or just the machine itself?  If just the machine,  
what 'names' does the front-end know the back-end instances by?

FWIW we use IP names for our 17 back-end UW mailstores...


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