General best practices with Java 8: If you have enough RAM for 24 GB heap, use G1 GC.If you have less RAM, then use CMS with a medium-sized heap setting so theGC time is not as long but more frequent. Graph memory use with Grafana or something and let people know what's happening.
https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsTuneJVM.html http://thelastpickle.com/blog/2018/04/11/gc-tuning.html Your cluster: Which version of Java? How much RAM do your systems have?Is it the same on all nodes?What are your current heap settings?Anything else? Thanks, James Briggs. -- Cassandra/MySQL DBA. Available in San Jose area or remote. cass_top: https://github.com/jamesbriggs/cassandra-top From: Rajasekhar Kommineni <rajaco...@gmail.com> To: user@cassandra.apache.org Sent: Monday, November 19, 2018 2:33 PM Subject: Long GC Pauses Hi All, My C cluster configuration. 1) 2 DC with 4 nodes each and Replication Factor of 3 per each DC 2) Writes(Bulk data load) are done to 2nd DC and Application (reads) are done from 1st DC. 3) CMS GC Issue : Observing long GC pauses during data load and timeouts from application (reads) during the same time. Question : 1)Why am I seeing GC pauses on 1st DC , even though I am using stream_throughput of 16 Mb/s. 2) Is there any way to reduce the GC pause times other than changing it. Thanks, --------------------------------------------------------------------- To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
