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 > > > > >
