What’s your disk latency? What kind of disk is it? -- Jacques-Henri Berthemet
From: onmstester onmstester [mailto:onmstes...@zoho.com] Sent: Monday, March 12, 2018 10:48 AM To: user <user@cassandra.apache.org> Subject: Re: yet another benchmark bottleneck 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. Sent using Zoho Mail<https://www.zoho.com/mail/> ---- On Mon, 12 Mar 2018 09:34:26 +0330 onmstester onmstester <onmstes...@zoho.com<mailto:onmstes...@zoho.com>> wrote ---- Apache-cassandra-3.11.1 Yes, i'm dosing a single host test Sent using Zoho Mail<https://www.zoho.com/mail/> ---- On Mon, 12 Mar 2018 09:24:04 +0330 Jeff Jirsa <jji...@gmail.com<mailto:jji...@gmail.com>> 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 <onmstes...@zoho.com<mailto:onmstes...@zoho.com>> wrote: I'm going to benchmark Cassandra's write throughput on a node with following spec: * 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 X.X.X.X 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. Sent using Zoho Mail<https://www.zoho.com/mail/>
