Running two instance of Apache Cassandra on same server, each having their own 
commit log disk dis not help. Sum of cpu/ram usage  for both instances would be 
less than half of all available resources. disk usage is less than 20% and 
network is still less than 300Mb in Rx.

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---- On Mon, 12 Mar 2018 09:34:26 +0330 onmstester onmstester 
<> wrote ----


Yes, i'm dosing a single host test

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---- On Mon, 12 Mar 2018 09:24:04 +0330 Jeff Jirsa <> 
wrote ----

Would help to know your version. 130 ops/second sounds like a ridiculously low 
rate. Are you doing a single host test? 

On Sun, Mar 11, 2018 at 10:44 PM, onmstester onmstester 
<> wrote:

I'm going to benchmark Cassandra's write throughput on a node with following 

CPU: 20 Cores

Memory: 128 GB (32 GB as Cassandra heap)

Disk: 3 seprate disk for OS, data and commitlog

Network: 10 Gb (test it with iperf)

Os: Ubuntu 16

Running Cassandra-stress:

cassandra-stress write n=1000000 -rate threads=1000 -mode native cql3 -node 

from two node with same spec as above, i can not get throughput more than 130 
Op/s. The clients are using less than 50% of CPU, Cassandra node uses:

60% of cpu

30% of memory

30-40% util in iostat of commitlog

300 Mb of network bandwidth

I suspect the network, cause no matter how many clients i run, cassandra always 
using less than 300 Mb. I've done all the tuning mentioned by datastax.

Increasing wmem_max and rmem_max did not help either.

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