If that is the case you could also try to run more stress from another machine as well.
-- Rahul Singh rahul.si...@anant.us Anant Corporation On Feb 18, 2018, 2:37 PM -0500, Jeff Jirsa <jji...@gmail.com>, wrote: > Stress client may be cpu bound as well > > -- > Jeff Jirsa > > > On Feb 18, 2018, at 7:40 AM, onmstester onmstester <onmstes...@zoho.com> > wrote: > > > I'm running tests on separate machine (not member of the cluster) > > I'm using the default data model of cassandra-stress tool : keyspace1 and > > table: standard1. nothing special on network or data traffic. Network > > capable of 1 G and tested it with ipperf. > > iftop shows maximum of 48Mbit traffic between nodes in cluster. > > Have not seen any warning in log files. > > I'm monitoring cassandra during runtime using jvisual vm and never saw any > > GC chokepoints, cpu is below 40% always. I just cant understand why > > cassandra is limmiting the throughput?! > > using top, fps and write per seconds are not showing any problems > > > > Sent using Zoho Mail > > > > > > ---- On Sun, 18 Feb 2018 18:42:48 +0330 Rahul Singh > > <rahul.xavier.si...@gmail.com> wrote ---- > > > > > Got it. > > > > > > Here are some other questions. > > > > > > Are you running the test on separate machine or one of the cluster > > > members? > > > > > > When configuring Cassandra stress what data model did you end up using? ( > > > do you see Data or traffic skew?) > > > > > > Do you see any wide partitions or Tombstone warnings on either node. > > > > > > Have you visualized the GC logs using something like VisualVM or hubspots > > > GC visualizer? This is to see if there are chokepoints in the GC cycle. > > > > > > > > > -- > > > Rahul Singh > > > rahul.si...@anant.us > > > > > > Anant Corporation > > > > > > On Feb 18, 2018, 9:23 AM -0500, onmstester onmstester > > > <onmstes...@zoho.com>, wrote: > > > > > > > But monitoring cassandra with jmx using jvisualVM shows no problem, > > > > less than 30% of heap size used > > > > > > > > Sent using Zoho Mail > > > > > > > > > > > > ---- On Sun, 18 Feb 2018 17:26:59 +0330 Rahul Singh > > > > <rahul.xavier.si...@gmail.com> wrote ---- > > > > > > > > > You don’t don’t have enough memory. That’s just a start. > > > > > > > > > > -- > > > > > Rahul Singh > > > > > rahul.si...@anant.us > > > > > > > > > > Anant Corporation > > > > > > > > > > On Feb 18, 2018, 6:29 AM -0500, onmstester onmstester > > > > > <onmstes...@zoho.com>, wrote: > > > > > > > > > > > I've configured a simple cluster using two PC with identical spec: > > > > > > cpu core i5 > > > > > > RAM: 8GB ddr3 > > > > > > Disk: 1TB 5400rpm > > > > > > Network: 1 G (I've test it with iperf, it really is!) > > > > > > > > > > > > using the common configs described in many sites including datastax > > > > > > itself: > > > > > > cluster_name: 'MyCassandraCluster' > > > > > > num_tokens: 256 > > > > > > seed_provider: > > > > > > - class_name: org.apache.cassandra.locator.SimpleSeedProvider > > > > > > parameters: > > > > > > - seeds: "192.168.1.1,192.168.1.2" > > > > > > listen_address: > > > > > > rpc_address: 0.0.0.0 > > > > > > endpoint_snitch: GossipingPropertyFileSnitch > > > > > > > > > > > > Running stress tool: > > > > > > cassandra-stress write n=1000000 -rate threads=1000 -mode native > > > > > > cql3 -node 192.168.1.1,192.168.1.2 > > > > > > > > > > > > Over each node it shows 39 K writes/seconds, but running the same > > > > > > stress tool command on cluster of both nodes shows 45 K > > > > > > writes/seconds. I've done all the tuning mentioned by apache and > > > > > > datastax. There are many use cases on the net proving Cassandra > > > > > > linear Scalability So what is wrong with my cluster? > > > > > > > > > > > > Sent using Zoho Mail > > > > > > > > > > > > > >
