Sorry Alain,maybe some misunderstanding here,I mean to disable Compaction in the bootstrapping process,then enable it after the bootstrapping.
------------------ ???????? ------------------ ??????: "????????????"<2535...@qq.com>; ????????: 2018??3??23??(??????) ????10:54 ??????: "user"<user@cassandra.apache.org>; ????: ?????? disable compaction in bootstrap process Thanks Alain.We are using C* 2.1.18,7core/30G/1.5T ssd,as the cluster is growing too fast,we are painful in bootstrap/rebuild/remove node. Thanks, Peng Xiao ------------------ ???????? ------------------ ??????: "Alain RODRIGUEZ"<arodr...@gmail.com>; ????????: 2018??3??22??(??????) ????7:31 ??????: "user cassandra.apache.org"<user@cassandra.apache.org>; ????: Re: disable compaction in bootstrap process Hello, Is it reasonable to disable compaction on all the source node? I would say no, as a short answer. You can, I did it for some operations in the past. Technically no problem you can do that. It will most likely improve the response time of the queries immediately as it seems that in your cluster compactions are impacting the transactions. That being said, the impact in the middle/long term will be substantially worst. Compactions allow fragments of rows to be merged so the reads can be more efficient, hitting the disk just once ideally (at least to reach a reasonably low number of hits on the disk). Also, when enabling compactions back you might have troubles again as compaction will have to catch up. Imho, disabling compaction should be an action to take unless your understanding about compaction is good enough and you are in a very specific case that requires it. In any case, I would recommend you to stay away from using this solution as a quick workaround. It could lead to really wrong situations. Without mentioning tombstones that would stack there. Plus, doing this on all the nodes at once is really calling for troubles as all the nodes performances might degrade at the same pace, roughly. I would suggest a troubleshooting on why compactions are actually impacting the read/write performances. We probably can help with this here as I believe all the Cassandra users had to deal with this at some point (at least people running with 'limited' hardware compared to the needs). Here are some questions that I believe might be useful for us to help you or even for you to troubleshoot. - Is Cassandra limiting thing or resources reaching a limit? - Is the cluster CPU or Disk bounded? - What are the number of concurrent compactors and compaction speed in use? - What hardware are you relying on? - What version are you using? - Is compaction keeping up? What compactions strategy are you using? - 'nodetool tpstats' might also give information on pending and dropped tasks. It might be useful. C*heers, ----------------------- Alain Rodriguez - @arodream - al...@thelastpickle.com France / Spain The Last Pickle - Apache Cassandra Consulting http://www.thelastpickle.com 2018-03-22 9:09 GMT+00:00 Peng Xiao <2535...@qq.com>: Dear All, We noticed that when bootstrap new node,the source node is also quite busy doing compactions which impact the rt severely.Is it reasonable to disable compaction on all the source node? Thanks, Peng Xiao
