Hi Everyone, I need some suggestions on finding the time taken for Cassandra replication to happen from east to west region for write and read operations on a multi DC cluster. Currently, below is our cluster setup.
*Cassandra version:* DSE 5.0.7 *No of Data centers:* 2 (AWS East and AWS West regions) *No of Nodes:* 12 nodes (6 nodes in AWS East and 6 nodes in AWS West) *Replication Factor:* 3 in each data center. *Cluster size*: Around 40 GB on each node Sometime, next year we have an activity where our clients are going to be reading only from AWS West region. The data center in AWS east will be available but we do not want any reads to be done on this.(Our management wants to know the time it takes for Cassandra to replicate from one DC to the other) Here are some options I have thought of in finding the time taken for Cassandra replication to happen from AWS East DC to AWS West DC. 1. Setup a Java client to write/read a transaction with *"Local Quorum" *consistency level in* AWS East* region as Local data center, capture the time taken for this activity. Similarly use this client to perform read/write transaction with *"Local Quorum"* consistency level in *AWS West* region and capture the time. Then finally perform the same transaction with with *"Each Quorum" *consistency level and capture the time. *Inter DC latency* = *Time taken for Each Quorum transaction* *-* *(Time taken for Local Quorum transaction in AWS East as local dc)* *-** (Time taken for Local Quorum transaction in AWS West as local dc)*. 2. Utilize the https://github.com/gitaroktato/cassandra-replication-latency-tools open source project where a Python Cassandra clients writes in one Data Center and other client reads in other data center. Can you please suggest if my strategies above will help in finding the Inter DC latency or there are other ways I need to follow. Thank You, Bill Walters.
