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<DIV>Thanks, Michael. Actually round-robins dispatching doesn't fit my situation
well. If two consumers exist, they will get the message almost in the same time.
In this way, the order of the messages cannot be assured. I wonder if there is
some way that the server will send the message the second consumer only after it
receives the ACK from the first consumer.</DIV>
<DIV> </DIV>
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<DIV><SPAN>johnson</SPAN></DIV>
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<DIV><B>From:</B> <A href="mailto:Michael.Laing@nytimes.com">Laing, Michael
P.</A></DIV>
<DIV><B>Date:</B> 2012-08-25 03:12</DIV>
<DIV><B>To:</B> <A
href="mailto:rabbitmq-discuss@lists.rabbitmq.com">rabbitmq</A>; <A
href="mailto:johnson@edocom.cn">johnson</A></DIV>
<DIV><B>Subject:</B> Re: [rabbitmq-discuss] How to achieve HA
consumers?</DIV></DIV></DIV>
<DIV>
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<DIV>Actually, rereading, perhaps my solution is different from yours��</DIV>
<DIV><BR></DIV><SPAN id=OLK_SRC_BODY_SECTION>
<DIV
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style="FONT-WEIGHT: bold">From: </SPAN>Michael Laing <<A
href="mailto:Michael.Laing@nytimes.com">Michael.Laing@nytimes.com</A>><BR><SPAN
style="FONT-WEIGHT: bold">Reply-To: </SPAN>rabbitmq <<A
href="mailto:rabbitmq-discuss@lists.rabbitmq.com">rabbitmq-discuss@lists.rabbitmq.com</A>><BR><SPAN
style="FONT-WEIGHT: bold">Date: </SPAN>Fri, 24 Aug 2012 13:54:15 -0400<BR><SPAN
style="FONT-WEIGHT: bold">To: </SPAN>johnson <<A
href="mailto:johnson@edocom.cn">johnson@edocom.cn</A>>, rabbitmq <<A
href="mailto:rabbitmq-discuss@lists.rabbitmq.com">rabbitmq-discuss@lists.rabbitmq.com</A>><BR><SPAN
style="FONT-WEIGHT: bold">Subject: </SPAN>Re: [rabbitmq-discuss] How to achieve
HA consumers?<BR></DIV>
<DIV><BR></DIV>
<DIV>
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style="FONT-FAMILY: Calibri, sans-serif; WORD-WRAP: break-word; COLOR: rgb(0,0,0); FONT-SIZE: 14px; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space">
<DIV>I use your option 1: below, which works well.</DIV>
<DIV><BR></DIV>
<DIV>All critical services drive from HA queues and have at least one worker
(consumer) connected to each node in the cluster. RabbitMQ round-robins messages
to the workers. If a worker or node fails, its message is routed to another
worker.</DIV>
<DIV><BR></DIV>
<DIV>Michael</DIV><SPAN id=OLK_SRC_BODY_SECTION>
<DIV
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style="FONT-WEIGHT: bold">From: </SPAN>johnson <<A
href="mailto:johnson@edocom.cn">johnson@edocom.cn</A>><BR><SPAN
style="FONT-WEIGHT: bold">Reply-To: </SPAN>johnson <<A
href="mailto:johnson@edocom.cn">johnson@edocom.cn</A>>, rabbitmq <<A
href="mailto:rabbitmq-discuss@lists.rabbitmq.com">rabbitmq-discuss@lists.rabbitmq.com</A>><BR><SPAN
style="FONT-WEIGHT: bold">Date: </SPAN>Fri, 24 Aug 2012 12:30:01 -0400<BR><SPAN
style="FONT-WEIGHT: bold">To: </SPAN>rabbitmq <<A
href="mailto:rabbitmq-discuss@lists.rabbitmq.com">rabbitmq-discuss@lists.rabbitmq.com</A>><BR><SPAN
style="FONT-WEIGHT: bold">Subject: </SPAN>[rabbitmq-discuss] How to achieve HA
consumers?<BR></DIV>
<DIV><BR></DIV>
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<DIV>Hi,</DIV>
<DIV> </DIV>
<DIV>One problem I encountered is how to achieve HA consumers. My situation is
the following.</DIV>
<DIV> </DIV>
<DIV>I installed 1 consumer in a server to consume the messages.
But in the production environment, to avoid the unexceptional crash of the
consumer, I need to install another consumer in another server. However, because
the order of the messages are very important, if two consumers receive
the messages simultaneously, the order cannot be reserved.</DIV>
<DIV> </DIV>
<DIV>Maybe the following 2 way can work.</DIV>
<DIV>1: At the same time, the server only sends the message to 1 consumer.
After that consumer return a ACK, the server send the message to another
consumer. This means that although two consumers exist, they receive the
messages in turn <SPAN id=result_box lang=en class=short_text c="4"
a="undefined" closure_uid_hna1tc="117"><SPAN closure_uid_hna1tc="201">not
concurrently. Once 1 consumer crashes, the remaining consumer can still
work.</SPAN></SPAN></DIV>
<DIV><SPAN lang=en class=short_text c="4" a="undefined"
closure_uid_hna1tc="117"><SPAN
closure_uid_hna1tc="201"></SPAN></SPAN> </DIV>
<DIV><SPAN lang=en class=short_text c="4" a="undefined"
closure_uid_hna1tc="117"><SPAN closure_uid_hna1tc="201">2: 2 consumers work like
master-slave. Only 1 consumer works and the other one doesn't consume any
message. Once 1 consumer crashes, the remaining consumer will be
activated.</SPAN></SPAN></DIV>
<DIV> </DIV>
<DIV>I have searched a lot of RabbitMQ docs and couldn't find useful info. Could
anyone can give me some clue? Thanks a lot.</DIV>
<DIV> </DIV>
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<DIV><SPAN>johnson</SPAN></DIV></DIV></DIV></SPAN></DIV></DIV></SPAN></DIV></DIV></BODY></HTML>