Mailing-List: contact activemq-users-help@geronimo.apache.org; run by ezmlm
Precedence: bulk
Reply-To: activemq-users@geronimo.apache.org
Received-SPF: pass (asf.osuosl.org: domain of james.strachan@gmail.com
 designates 66.249.82.195 as permitted sender)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
        s=beta; d=gmail.com;
        h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references;
        b=jQjqJ9RunfBjHuLOc4LyNQAm4EbYDjp03t1UmeZMD38CcnUABvlVnrA1066w0knlGPjarl4pP6jlVwAeqq3vdVAbCAcchzdzCRuZxMfe0NFEFGkCg9qQ3ycyk3SIns3hpojYNm95svIPh+A65TwbC0PgKvDYQI+kP0o6iRL0eiA=
Message-ID: <ec6e67fd0608030742r128f788aw93ff7bb47162971e@mail.gmail.com>
Date: Thu, 3 Aug 2006 15:42:24 +0100
From: "James Strachan" <james.strachan@gmail.com>
To: activemq-users@geronimo.apache.org
Subject: Re: Question about clustering and reliable delivery
In-Reply-To: <5632611.post@talk.nabble.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
References: <5632611.post@talk.nabble.com>

On 8/3/06, Abdul Alhazred <tharter@tradedesksoftware.com> wrote:
>
> OK, here's the scenario:
>
> I have a number of producers, which produce a rather large number of
> messages, thus I need to be able to direct these messages to a set of
> clustered ActiveMQ brokers, and likewise there are numbers of consumers on
> the other side of the cluster receiving these messages.
>
> So far this is all fine, but these messages MUST be guaranteed delivered and
> processed in order. Exclusive Consumer is fine for this. Now what happens if
> the database server backing one of the brokers in the cluster fails? Both
> the consumers and producers can fail over to another broker, but now
> whatever messages are stored in that particular database are GONE (IE any
> which haven't yet been consumed).

The assumption is that the file or database is reliable. Failing that
you can use Master/Slave to replicate to different disks.

http://incubator.apache.org/activemq/masterslave.html


> What would be a recommended solution? It looks like ActiveMQ 4.1's JDBC
> master/slave would be a good answer, but I'd really like to have a solution
> I can deploy in the near term.

JDBC master/slave works great today - assuming you have reilable
databases. Though its fairly slow since it requires you to disable the
high performance journal.

Using a shared file system Master/Slave or using straight Master/Slave
is probably your best option if you have high performance requirements


> Pure database replication doesn't appear to
> be a real answer because master/slave replication in RDBMS are asynchronous
> (thus the slave database server might not yet have received all updates at
> the point where the crash occured). Besides in that case it would seem a new
> broker would have to join the cluster and start up using the replica
> database, which brings up various issues with what would happen with
> ordering of message delivery in the mean time.

Ordering is guarrenteed with Shared-FileSystem and JDBC based Master/Slaves.
-- 

James
-------
http://radio.weblogs.com/0112098/