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