For what its worth, I highly recommend you remove that option in all cassandra clusters first thing. A possibly non existent improvement (ie /tmp on different low throughput drive) vs being able to diagnose issues is a no brainer. You can measure or monitor gc logs for your safepoint pauses to see if its ever a significant portion of your GC pauses.
Chris On Thu, Sep 20, 2018 at 6:05 AM Philip Ó Condúin <philipocond...@gmail.com> wrote: > Thank you Yuki, this explains it. > I am used to working on C* 2.1 in production where this JVM flag is not > enabled. > > > On Wed, 19 Sep 2018 at 00:29, Yuki Morishita <mor.y...@gmail.com> wrote: > >> This is because Cassandra sets -XX:+PerfDisableSharedMem JVM option by >> default. >> This prevents tools such as jps to list jvm processes. >> See https://issues.apache.org/jira/browse/CASSANDRA-9242 for detail. >> >> You can work around by doing what Riccardo said. >> On Tue, Sep 18, 2018 at 9:41 PM Philip Ó Condúin >> <philipocond...@gmail.com> wrote: >> > >> > Hi Riccardo, >> > >> > Yes that works for me: >> > >> > Welcome to JMX terminal. Type "help" for available commands. >> > $> open localhost:7199 >> > #Connection to localhost:7199 is opened >> > $>domains >> > #following domains are available >> > JMImplementation >> > ch.qos.logback.classic >> > com.sun.management >> > java.lang >> > java.nio >> > java.util.logging >> > org.apache.cassandra.db >> > org.apache.cassandra.hints >> > org.apache.cassandra.internal >> > org.apache.cassandra.metrics >> > org.apache.cassandra.net >> > org.apache.cassandra.request >> > org.apache.cassandra.service >> > $> >> > >> > I can work with this :-) >> > >> > Not sure why the JVM is not listed when issuing the JVMS command, maybe >> its a server setting, our production servers find the Cass JVM. I've spent >> half the day trying to figure it out so I think I'll just put it to bed now >> and work on something else. >> > >> > Regards, >> > Phil >> > >> > On Tue, 18 Sep 2018 at 13:34, Riccardo Ferrari <ferra...@gmail.com> >> wrote: >> >> >> >> Hi Philip, >> >> >> >> I've used jmxterm myself without any problems particular problems. On >> my systems too, I don't get the cassandra daemon listed when issuing the >> `jvms` command but I never spent much time investigating it. >> >> Assuming you have not changed anything relevant in the >> cassandra-env.sh you can connect using jmxterm by issuing 'open >> 127.0.0.1:7199'. Would that work for you? >> >> >> >> HTH, >> >> >> >> >> >> >> >> On Tue, Sep 18, 2018 at 2:00 PM, Philip Ó Condúin < >> philipocond...@gmail.com> wrote: >> >>> >> >>> Further info: >> >>> >> >>> I would expect to see the following when I list the jvm's: >> >>> >> >>> Welcome to JMX terminal. Type "help" for available commands. >> >>> $>jvms >> >>> 25815 (m) - org.apache.cassandra.service.CassandraDaemon >> >>> 17628 ( ) - jmxterm-1.0-alpha-4-uber.jar >> >>> >> >>> But jmxtem is not picking up the JVM for Cassandra for some reason. >> >>> >> >>> Can someone point me in the right direction? Is there settings in >> the cassandra-env.sh file I need to amend to get jmxterm to find the cass >> jvm? >> >>> >> >>> Im not finding much about it on google. >> >>> >> >>> Thanks, >> >>> Phil >> >>> >> >>> >> >>> On Tue, 18 Sep 2018 at 12:09, Philip Ó Condúin < >> philipocond...@gmail.com> wrote: >> >>>> >> >>>> Hi All, >> >>>> >> >>>> I need a little advice. I'm trying to access the JMX terminal using >> jmxterm-1.0-alpha-4-uber.jar with a very simple default install of C* 3.11.3 >> >>>> >> >>>> I keep getting the following: >> >>>> >> >>>> [cassandra@reaper-1 conf]$ java -jar jmxterm-1.0-alpha-4-uber.jar >> >>>> Welcome to JMX terminal. Type "help" for available commands. >> >>>> $>open 1666 >> >>>> #NullPointerException: No such PID 1666 >> >>>> $> >> >>>> >> >>>> C* is running with a PID of 1666. I've tried setting JMX_LOCAL=no >> and have even created a new VM to test it. >> >>>> >> >>>> Does anyone know what I might be doing wrong here? >> >>>> >> >>>> Kind Regards, >> >>>> Phil >> >>>> >> >>> >> >>> >> >>> -- >> >>> Regards, >> >>> Phil >> >> >> >> >> > >> > >> > -- >> > Regards, >> > Phil >> > > > -- > Regards, > Phil >
