[rabbitmq-discuss] RabbitMq Server how to make master-slave and master-backup ?

[Simon MacMullen]

On 26/11/13 07:25, Michael Klishin wrote:
> On 26 Nov 2013, at 10:15, 3k4b251 <314992959 at qq.com> wrote:
>
>> rabbitmq  server  use
>> one,  and  copy  data  to  the other database  at the same time   or  a
>> time later .
>
> It’s only safe to copy Mnesia directory when RabbitMQ node that uses it is not running.

Depends how safe you want to be. It *is* possible to do active/passive 
failover by having two brokers share one data directory; we documented 
one such approach here:

http://www.rabbitmq.com/pacemaker.html

There are multiple disadvantages though:

* Setting it up is a PITA.

* At failover the "spare" broker will need to rebuild indexes from 
scratch (possibly taking a long time).

* The safety of (confirmed) messages is less guaranteed than with 
mirrored queues. In practice you tend not to lose much if anything. But 
in theory everything could vanish.

* As with all active / passive systems failover is such a big deal that 
you never tend to test it.

So that's why we recommend mirrored queues instead. Or...

> If you want a hot standby, use Shovel or federated exchanges to replicate messages.

...these are also good options.

Cheers, Simon

-- 
Simon MacMullen
RabbitMQ, Pivotal