Hi, I am running a performance test for Cassandra 1.0.5. It can perform about 1500 business operation (one read+one write to the same row) per second. However, the CPU is still 85% idle (as shown by vmstat) and the IO utilization is less than a few percent (as shown by iostat). "nodetool tpstats" shows basically no active and pending threads. I can run several such test clients concurrently, achieving the same operations per second without increasing the hardware utilization. So, why the performance has reached a plateau while there is still idle hardware resources?
Thanks in advance for any idea!
