Cassandra read/write bandwidth
|Added at||2017-01-02 17:01|
I'm using Cassandra docker latest. I'm running multiple containers, each run a stand alone Cassandra instance. Each instance has a local nvme SSD to store data and commit log on it. I'm working with YCSB to test performance- workload a (50% reads 50% inserts) 100M records. for 2 containers on a single host I'm getting ~23K TPS.
What I don't understand is the nvme ssd performance: I see a steady ~2GB/s read bandwidth on each ssd and only ~ 20MB/s writes. The writes are done only for a short time- most of the time there are no writes to the disks and once in a while I can see a peak of 300MB/s writes.
is that an expected behavior of Cassandra? is the rate between disks reads to writes is so huge?
(the host has 65GB Memory)