---
sidebar_label: "start"
sidebar_position: 3
---

import { Table } from "docs-ui"

export const metadata = {
  title: `start Command - Medusa CLI Reference`,
}

# {metadata.title}

Start the Medusa application in production.

```bash
npx medusa start
```

## Options

<Table>
  <Table.Header>
    <Table.Row>
      <Table.HeaderCell>Option</Table.HeaderCell>
      <Table.HeaderCell>Description</Table.HeaderCell>
      <Table.HeaderCell>Default</Table.HeaderCell>
    </Table.Row>
  </Table.Header>
  <Table.Body>
    <Table.Row>
      <Table.Cell>
      
      `-H <host>`, `--host <host>`
      
      </Table.Cell>
      <Table.Cell>

      Set host of the Medusa server.
      
      </Table.Cell>
      <Table.Cell>

      `localhost`

      </Table.Cell>
    </Table.Row>
    <Table.Row>
      <Table.Cell>
      
      `-p <port>`, `--port <port>`
      
      </Table.Cell>
      <Table.Cell>

      Set port of the Medusa server.
      
      </Table.Cell>
      <Table.Cell>

      `9000`

      </Table.Cell>
    </Table.Row>
    <Table.Row>
      <Table.Cell>
      
      `--cluster <string> [--workers <string>] [--servers <string>]`
      
      </Table.Cell>
      <Table.Cell>

      Start Medusa in cluster mode. Learn more in the [Starting Medusa in Cluster Mode](#starting-medusa-in-cluster-mode) section.
      
      </Table.Cell>
      <Table.Cell>

      Cluster mode is disabled by default. If the option is passed but no number or percentage is passed, Medusa will try to consume all available CPU cores.

      </Table.Cell>
    </Table.Row>
  </Table.Body>
</Table>

---

## Starting Medusa in Cluster Mode

<Note>

Prior to [Medusa v2.11.0](https://github.com/medusajs/medusa/releases/tag/v2.11.0), the `--cluster` option accepted a number value only. You can now pass either a number or a percentage value, and you can also specify the number of servers and workers.

</Note>

Medusa supports starting the Node.js server in [cluster mode](https://expressjs.com/en/advanced/best-practice-performance.html#run-your-app-in-a-cluster), which significantly improves performance as the workload and tasks are distributed among all available instances instead of a single one.

Cluster mode is disabled by default. To enable it, pass the `--cluster` option when starting Medusa:

```bash
npx medusa start --cluster
```

When the `--cluster` option is passed without a number or percentage value, Medusa will try to consume all available CPU cores.

### Specify Number or Percentage of CPU Cores

You can specify the number or percentage of CPU cores to be used by passing a number or percentage value to the `--cluster` option:

```bash
npx medusa start --cluster 2       # Use 2 CPU cores
npx medusa start --cluster 50%      # Use 50% of available CPU
```

### Specify Number of Servers and Workers

When running Medusa in cluster mode, you can specify the number or percentage of instances that are [servers or workers](!docs!/learn/production/worker-mode) by passing the `--servers` and `--workers` options:

```bash
npx medusa start --cluster 4 --servers 25% --workers 75% # Use 4 CPU cores, with 25% as servers and 75% as workers
npx medusa start --cluster 4 --servers 1 --workers 3       # Use 4 CPU cores, with 1 as server and 3 as workers
npx medusa start --cluster 4 --servers 1 --workers 1      # Use 4 CPU cores, with 1 as server and 1 as worker (the remaining 2 will run in shared mode)
```

When the number or percentage of servers and workers don't add up to the total number of instances in cluster mode, the remaining instances will run in shared mode.

<Note>

Learn more in the [Worker Mode](!docs!/learn/production/worker-mode) guide.

</Note>