When they say "linear scalibility" they mean "throughput scales with the amount of machines in your cluster".
Try adding more machines to your cluster and measure the thoughput. I'm pretty sure you'll see linear scalibility. regards, Christian On Tue, Jul 17, 2012 at 6:13 AM, Code Box <codeith...@gmail.com> wrote: > I am doing Cassandra Benchmarking using YCSB for evaluating the best > performance for my application which will be both read and write intensive. > I have set up a three cluster environment on EC2 and i am using YCSB in the > same availability region as a client. I have tried various combinations of > tuning cassandra parameters like FSync ( Setting to batch and periodic ), > Increasing the number of rpc_threads, increasing number of concurrent reads > and concurrent writes, write consistency one and Quorum i am not getting > very great results and also i do not see a linear graph in terms of > scalability that is if i increase the number of clients i do not see an > increase in the throughput. > > Here are some sample numbers that i got :- > > *Test 1:- Write Consistency set to Quorum Write Proportion = 100%. FSync > = Batch and Window = 0ms* > > ThreadsThroughput ( write per sec ) Avg Latency (ms)TP95(ms) TP99(ms) > Min(ms)Max(ms) > > > 102149 3.1984 51.499291 1004070 23.82870 2.2260 2004151 45.96571301.7 > 1242 300419764.68 1154222.09 216 > > > If you look at the numbers the number of threads do not increase the > throughput. Also the latency values are not that great. I am using fsync > set to batch and with 0 ms window. > > *Test 2:- ** Write Consistency set to Quorum Write Proportion = 100%. > FSync = Periodic and Window = 1000 ms* > * > * > 1803 1.23712 1.012312.9Q 10015944 5.343925 1.21579.1Q 200196309.047 1970 > 1.17 1851Q > Are these numbers expected numbers or does Cassandra perform better ? Am i > missing something ? >
