incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Kent Tong <>
Subject performance reaching plateau while the hardware is still idle
Date Thu, 15 Dec 2011 10:58:33 GMT

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!

View raw message