High Availability approaches for Cyrus

[Michael Menge]

Quoting "Simpson, John R" <john_simpson at reyrey.com>:

> Greetings all,
>
>             I've spent a good deal of time searching the Info-Cyrus  
> archives (and various googled articles) to identify the recommended  
> ways to improve Cyrus availability and reduce disaster recovery  
> time.  The two main approaches appear to be Cyrus replication and  
> file system replication using DRBD and Heartbeat/Pacemaker/RHCS.   
> Cyrus replication appears to be the preferred approach, since with  
> DRBD a corrupted file system on the master would be replicated on  
> the slave.  I have a few questions.
>
> - Am I missing something?  Is there a third approach that is better  
> than Cyrus or file system replication?

I don't know any other.

> - Cyrus replication seems to be used in conjunction with manual  
> failover procedures.  Is anyone using Heartbeat, etc. with Cyrus  
> replication?

You could write scripts to do the failover with Heartbeat, but IMHO
the reaction-time you win by using Heartbeat does not outwight the risk
of an ammok running Heartbeat (e.g. split brain)

> - We have three Cyrus servers, each with a single large mailstore.   
> Would there be a significant advantage to splitting them into  
> multiple smaller mailstores?  We're using Perdition but not Murder /  
> Aggregator.

Running two active instances of cyrus would allow you to share the  
load of the failed server on the two other instead of one server doing  
the work of two.

> - Are there any situations where DRBD would be preferred to Cyrus  
> replication?

Cyrus replication is very new, so you have to use a recent version of  
cyrus. If you have to use an older version of cyrus DRBD might be the  
only option.

>
> Thank you for your time.
>
> John
>
> John Simpson
> Senior Software Engineer, I. T. Engineering and Operations
>
>



--------------------------------------------------------------------------------
M.Menge                                Tel.: (49) 7071/29-70316
Universität Tübingen                   Fax.: (49) 7071/29-5912
Zentrum für Datenverarbeitung          mail:  
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