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Scaling Node.JS

Three areas to take care in scaling

  1. Multiple instances
  2. Microservices
  3. Database Partitioning
How to fork?
const { fork } = require('child-process);

const processes = [
  fork('./app', ['3001']),
  fork('./app', ['3002']),
  fork('./app', ['3003'])
]
Check CPUs on machine
const cpus = require('os').cpus;
console.log(cpus);
Run as many instances of node app as many CPUs are available. Write the following to index.js and run in Node



const http = require('http');



const cluster = require('cluster');



const cpus_len = require('os').cpus().length;



if (cluster.isMaster) {



    console.log("FORKING", process.pid);



    for (let i = 0; i < cpus_len; i++) {



        cluster.fork();



    }



} else {



    http.createServer((req, res) => {



        res.end(process.pid.toString());



    }).listen(3000);



}

LoadTest

LoadTest can be used to test multiple processes running.
Installing LoadTest
npm install loadtest
loadtest -n 500 http://localhost:3000

Scaling using PM2

Installing PM2

npm install pm2

Running PM2

pm2 start index.js -i -1

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