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From Torsten Mielke <tors...@fusesource.com>
Subject Re: pure master/slave question - console of slave shows many pending msgs
Date Wed, 31 Oct 2012 19:36:13 GMT
Hello Mike,

5.5.1 or later should not have these problems with pure master/slave setup.
I can also confirm that 5.5.1 and later versions work correctly with JDBC and shared file
system master/slave. 
So if somehow possible you should upgrade to the latest version. There anyway won't be any
bug fixes done on the 5.3 5.4 and 5.5 branches at Apache.

The HA and Failover features have been hardened a lot since 5.3. 


On the technical side:

>>> Mostly, I want assurance that the slave is not continuing to store messages that
were consumed/acknowledged from the master. (In other words, should the master fail, then
clients aren't going to get a bunch of duplicate messages...)

You can verify by taking a copy of the persistence adapter and start an isolated broker using
that copy. Then check the brokers JMX statistics and try to browse the messages.
On 5.3 I personally could not give you the assurance you are asking for. 


Best Regards,

Torsten Mielke
torsten@fusesource.com
tmielke.blogspot.com


On Oct 31, 2012, at 4:25 PM, Mike L. wrote:

> 
> Torsten:
> 
> Thank you for your reply. There are two reasons we are still on 5.3.1
> 
> 1. In TEST I see we have tried 5.3.1; 5.4.1; 5.5.0; and 5.5.1
> We also use Camel and in testing when I had ActiveMQ 5.4.1 up & running the request-response
pattern would very often timeout for us (which was unacceptable). I finally concluded that
this did not happen on 5.3.1 - and this was approximately two years ago; I'm pretty sure 5.5
wasn't even out yet.
> 
> 2. In our production environment we have five separate applications using ActiveMQ. We
would have to have a coordinated downtime of all 5 in order to upgrade to a more recent version.
Also, given my experience with 5.4.1 I was reticent to replace 5.3.1 which has been running
like a champ...
> 
> Finally, I would prefer to use a shared JDBC master/slave. However, we are using Oracle
RAC and my testing has never been able to have the active ActiveMQ server failover to the
secondary oracle rac server. (I have seen similar posts from others when searching on this
topic).
> 
> Any thoughts/tips are welcome!
> 
> Thanks again,
> 
> Mike (aka patzerbud)
> 
> 
>> Subject: Re: pure master/slave question - console of slave shows many pending msgs
>> From: torsten@fusesource.com
>> Date: Wed, 31 Oct 2012 14:04:20 +0100
>> To: users@activemq.apache.org
>> 
>> Hi,
>> 
>> Message replication should work correctly in pure master/slave setup on a decent
version of ActiveMQ.
>> 5.3 is rather old. Any reason for using that old version?
>> 
>> Also, pure master/slave has some drawback (which are documented). Are you sure you
don't want to use other models of master/slave?
>> 
>> 
>> Regards, 	   		  
>> 
>> Torsten Mielke
>> torsten@fusesource.com
>> tmielke.blogspot.com
>> 
>> 
>> 
>> 
>> On Oct 30, 2012, at 10:31 PM, Mike L. wrote:
>> 
>>> 
>>> All:
>>> 
>>> I have configured a pure (shared nothing) master/slave setup (both are running
ActiveMQ 5.3.1). 
>>> 
>>> One of the documentation points for this configuration is: 
>>> 
>>> A slave of a master broker consumes all message states from the master - messages,
acknowledgments and transactional states.
>>> 
>>> However, when I view the admin console of the slave (http://slaveip:8161/admin/queues.jsp)
for many queues I see the "Number Of Pending Messages" is all over the map. That is, sometimes
it equals the "Messages Enqueued" count; sometimes it is zero; and sometimes it is about halfway
in between. By the way, if I click on a queue name on this page it "spins" but never comes
back.
>>> 
>>> Mostly, I want assurance that the slave is not continuing to store messages that
were consumed/acknowledged from the master. (In other words, should the master fail, then
clients aren't going to get a bunch of duplicate messages...)
>>> 
>>> TIA,
>>> 
>>> Mike (aka patzerbud)
>>> 
>>> 	
> 		 	   		  






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