<html><head></head><body bgcolor="#FFFFFF"><div>Don't take this as gospel, yet, but my understanding is that you'll be able to make cluster changes like this successfully, but I'll make sure there's a test case to prove this scenario.</div><div><br>On 1 Oct 2012, at 18:07, Matt Pietrek <<a href="mailto:mpietrek@skytap.com">mpietrek@skytap.com</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>Hey Tim,<br><br>I was expecting that basic response. Thanks!<br><br>However... I still think there may an issue here that hinders RabbitMQ's deployment in production scenarios. Please correct me if I'm wrong or missing something.<br>
<br>Hypothetically, what would happen if my 'util' node was zapped by lightning and I had no way to bring it up in a timely manner. Would I be able to start the existing cluster nodes (play, play2) "far enough" to run the proper rabbitmqctl command to remove util from the cluster?<br>
<br>That is, once I've gotten into a bad situation, can I back out of it gracefully and without message loss? Or is the only option to reset the entire cluster?<br><br>Thanks,<br><br>Matt<br><div class="gmail_quote">On Mon, Oct 1, 2012 at 3:04 AM, Tim Watson <span dir="ltr"><<a href="mailto:tim@rabbitmq.com" target="_blank">tim@rabbitmq.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
Hi Matt,<div class="im"><br>
<br>
On 09/28/2012 08:23 PM, Matt Pietrek wrote:<br>
<blockquote type="cite">For example, at one point I had a three node cluster:
play, play2, and util. I then removed util from the cluster,
although to be honest, simply by changing the rabbitmq.config
file, rather than explicitly running rabbitmqctl stop_app while
the cluster is still running.<br>
<br>
</blockquote>
<br></div>
I'm pretty sure you're not supposed to do that! :)<div class="im"><br>
<br>
<blockquote type="cite">My steps:<br>
<ul>
<li>Running as three node cluster, stop all brokers</li>
<li>Create a new rabbitmq.config file with just two brokers</li>
<li>Attempt to start the new cluster.</li>
</ul>
</blockquote>
<br></div>
If you don't take util offline using the right procedure, I suspect
mnesia will get out of sorts and this isn't something you want to
happen. It's important to make cluster changes using the right
procedure, as mnesia is rather a fussy beast.<br>
<br>
BTW we've made some improvements that (hopefully) simplify working
with clusters and these will be in the forthcoming feature release!
<br>
<br>
Cheers,<br>
Tim<br>
</div>
</blockquote></div><br>
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