<div dir="ltr">Ken,<div><br></div><div>The CIB file is not being updated that often.</div><div>I took a packet capture and don't see the node sending any message to other nodes (other than keep-alives).</div><div>What then explains these messages coming every second?</div><div><br></div><div>-Regards</div><div>Nikhil</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Sat, Apr 1, 2017 at 1:37 AM, Ken Gaillot <span dir="ltr"><<a href="mailto:kgaillot@redhat.com" target="_blank">kgaillot@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 03/31/2017 06:44 AM, Nikhil Utane wrote:<br>
> We are seeing this log in pacemaker.log continuously.<br>
><br>
> Mar 31 17:13:01 [6372] 0005B932ED72 cib: info:<br>
> crm_compress_string: Compressed 436756 bytes into 14635 (ratio 29:1) in<br>
> 284ms<br>
><br>
> This looks to be the reason for high CPU. What does this log indicate?<br>
<br>
</span>If a cluster message is larger than 128KB, pacemaker will compress it<br>
(using BZ2) before transmitting it across the network to the other<br>
nodes. This can hit the CPU significantly. Having a large resource<br>
definition makes such messages more common.<br>
<br>
There are many ways to sync a configuration file between nodes. If the<br>
configuration rarely changes, a simple rsync cron could do it.<br>
Specialized tools like lsyncd are more responsive while still having a<br>
minimal footprint. DRBD or shared storage would be more powerful and<br>
real-time. If it's a custom app, you could even modify it to use<br>
something like etcd or a NoSQL db.<br>
<span class=""><br>
><br>
> -Regards<br>
> Nikhil<br>
><br>
><br>
> On Fri, Mar 31, 2017 at 12:08 PM, Nikhil Utane<br>
</span><div><div class="h5">> <<a href="mailto:nikhil.subscribed@gmail.com">nikhil.subscribed@gmail.com</a> <mailto:<a href="mailto:nikhil.subscribed@gmail.com">nikhil.subscribed@<wbr>gmail.com</a>>> wrote:<br>
><br>
> Hi,<br>
><br>
> In our current design (which we plan to improve upon) we are using<br>
> the CIB file to synchronize information across active and standby nodes.<br>
> Basically we want the standby node to take the configuration that<br>
> was used by the active node so we are adding those as resource<br>
> attributes. This ensures that when the standby node takes over, it<br>
> can read all the configuration which will be passed to it as<br>
> environment variables.<br>
> Initially we thought the list of configuration parameters will be<br>
> less and we did some prototyping and saw that there wasn't much of<br>
> an issue. But now the list has grown it has become close to 300<br>
> attributes. (I know this is like abusing the feature and we are<br>
> looking towards doing it the right way).<br>
><br>
> So I have two questions:<br>
> 1) What is the best way to synchronize such kind of information<br>
> across nodes in the cluster? DRBD? Anything else that is simpler?<br>
> For e.g. instead of syncing 300 attributes i could just sync up the<br>
> path to a file.<br>
><br>
> 2) In the current design, is there anything that I can do to reduce<br>
> the CPU utilization of cib process? Currently it regularly takes<br>
> 30-50% of the CPU.<br>
> Any quick fix that I can do which will bring it down? For e.g.<br>
> configure how often it synchronizes etc?<br>
><br>
> -Thanks<br>
> Nikhil<br>
<br>
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