How can data be partitioned in Node.js without the risk of data loss?

The question about data separation in Node.js without the risk of data loss is usually related to maintaining state between processes or during scaling.

You can use the following approaches:

• External data storage. For example, Redis, databases (MongoDB, PostgreSQL), or file systems. Data is written to a reliable storage, which prevents loss during restart or failure.

• Using clustering with shared storage. Node.js supports clustering mode, but each process has its own memory. To share data, processes should access a common storage.

• Message queue mechanisms. RabbitMQ, Kafka, and others allow synchronizing data and events between processes.

• Transactions and write confirmations. To ensure data safety, it is important to use atomic operations and write confirmations.

Example with Redis:

const redis = require('redis');
const client = redis.createClient();

client.on('error', (err) => console.log('Redis Client Error', err));

async function saveData(key, value) {
  await client.connect();
  await client.set(key, value);
  await client.disconnect();
}

async function getData(key) {
  await client.connect();
  const value = await client.get(key);
  await client.disconnect();
  return value;
}

Thus, data is stored outside the Node.js process, minimizing the risk of loss.