Hi,
I am doing some performance benchmarks in a *single* node cassandra
1.2.4. BTW, the machine is dedicated to run one cassandra instance.
The workload is 100% write. The throughput varies dramatically and
sometimes even drops to 0. I have tried several things below and still
got the same
ParNew GC (used by default in cassandra) uses 'stop-the-world' algorithm,
which means your application has to be stopped to do gc.
You can run jstat command to monitor gc activity and check if your write
performance is related to GC, eg:
$ jstat -gc CASSANDRA_PID 1s
But it shouldn't drop
280 sec: 865658 operations; 2661.5 current ops/sec; [INSERT
AverageLatency(us)=3640.16]
290 sec: 865658 operations; 0 current ops/sec;
It also may indicate that C* trying to finished active tasks and your write
requests have been
in the queue all 10 sec. Try to monitor C* doing*$watch nodetool
