<div dir="ltr">So to confirm my understanding here. �Message 1 was synched to both queues before I stopped the disc node. �So when I shut down the disc node, the ram node become the "master". �As such, it should have had message 1 and 2. �When I brought up the disc node it is a slave and had it's messages essentially reset. �Per the docs: "<span style="color:rgb(85,85,85);font-family:Verdana,sans-serif;font-size:13px;line-height:18px">As such, when a slave rejoins a mirrored-queue, it throws away any durable local contents it already has and starts empty.".�</span>�So when I now publish message 2, that goes to the ram node, which is now the master, and we have 2 messages total (disc node still off). �<div>
<br></div><div style>The question becomes then - is there any way to recover the messages the RAM node had if the disc node comes back and the ram node subsequently failed? �Granted this is an unlikely situation, but I'm trying to plan for recover scenarios here :) �Do I need to remove the HA policy, then bring up the RAM node to get the RAM node messages (since it was master prior to it's restart)? �Since I can't shut off the disc node in this case, just trying to figure out how to recover. �I can see taking this a step further - if I had 3 nodes in a cluster, and 1 node went down, but the other 2 nodes each got an even distribution of the queues... hrmm, would make it somewhat interesting to recover. �I'd almost have to shutdown yet one more node, start up the original node, make sure that messages get consumed, then start the third node it sounds like. �</div>
<div style><br></div><div style>I've started testing on the new 3.1 nightly �- I'm hoping it makes this a lot cleaner!<br></div><div style>Thanks!<br>Jason</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">
On Fri, Apr 26, 2013 at 3:44 AM, Emile Joubert <span dir="ltr"><<a href="mailto:emile@rabbitmq.com" target="_blank">emile@rabbitmq.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
<br>
Hi Jason,<br>
<div class="im"><br>
On 25/04/13 21:09, Jason McIntosh wrote:<br>
> I have 2 nodes in an rabbit cluster, one disc, one ram node. �I'm seeing<br>
> messages get lost<br>
<br>
</div>The explanation can be found here:<br>
<a href="http://www.rabbitmq.com/ha.html#behaviour" target="_blank">http://www.rabbitmq.com/ha.html#behaviour</a><br>
<br>
�"should there be no slave that is synchronised with the master,<br>
� messages that only the master held will be lost."<br>
<br>
Messages can get lost if you recycle nodes in the cluster faster than it<br>
takes for the queue contents to be replaced entirely with new messages.<br>
The solution is to wait for slaves to become synchronised before<br>
restarting each node.<br>
<br>
The next version of RabbitMQ will feature manual eager synchronisation<br>
which will allow slaves to catch up on old messages held only on the<br>
master node. You can obtain this feature now by installing a nightly<br>
build of the broker, or wait for the next release.<br>
<span class="HOEnZb"><font color="#888888"><br>
<br>
-Emile<br>
<br>
<br>
<br>
<br>
<br>
</font></span></blockquote></div><br><br clear="all"><div><br></div>-- <br>Jason McIntosh<br><a href="http://mcintosh.poetshome.com/blog/">http://mcintosh.poetshome.com/blog/</a><br>573-424-7612
</div>