# Mounting your Amazon FSx file system automatically
<a name="mount-fs-auto-mount-onreboot"></a>

 You can update the `/etc/fstab` file in your Amazon EC2 instance after you connect to the instance for the first time so that it mounts your Amazon FSx file system each time it reboots.

## Using /etc/fstab to mount FSx for Lustre automatically
<a name="lustre-mount-fs-auto-mount-update-fstab"></a>

To automatically mount your Amazon FSx file system directory when the Amazon EC2 instance reboots, you can use the `fstab` file. The `fstab` file contains information about file systems. The command `mount -a`, which runs during instance startup, mounts the file systems listed in the `fstab` file.

**Note**  
Before you can update the `/etc/fstab` file of your EC2 instance, make sure that you've already created your Amazon FSx file system. For more information, see [Step 1: Create your FSx for Lustre file system](getting-started.md#getting-started-step1) in the Getting Started exercise.
For EFA-enabled file systems, configuring systemd is a pre-requisite. For more information, see [Quick setup](configure-efa-clients.md#quick-setup).

**To update the /etc/fstab file in your EC2 instance**

1. Connect to your EC2 instance, and open the `/etc/fstab` file in an editor.

1. Add the following line to the `/etc/fstab` file.

   Mount the Amazon FSx for Lustre file system to the directory that you created. Use the following command and replace the following:
   + Replace *`/fsx`* with the directory that you want to mount your Amazon FSx file system to.
   + Replace `file_system_dns_name` with the actual file system's DNS name.
   + Replace `mountname` with the file system's mount name. This mount name is returned in the `CreateFileSystem` API operation response. It's also returned in the response of the **describe-file-systems** AWS CLI command, and the `[DescribeFileSystems](https://docs.aws.amazon.com/fsx/latest/APIReference/API_DescribeFileSystems.html)` API operation.

   **For non-EFA file systems:**

   ```
   file_system_dns_name@tcp:/mountname /fsx lustre defaults,relatime,flock,_netdev,x-systemd.automount,x-systemd.requires=network.service 0 0
   ```

   **For EFA-enabled file systems:**

   ```
   file_system_dns_name@tcp:/mountname /fsx lustre defaults,relatime,flock,_netdev,x-systemd.automount,x-systemd.requires=configure-efa-fsx-lustre-client.service,x-systemd.after=configure-efa-fsx-lustre-client.service 0 0
   ```
**Warning**  
Use the `_netdev` option, used to identify network file systems, when mounting your file system automatically. If `_netdev` is missing, your EC2 instance might stop responding. This result is because network file systems need to be initialized after the compute instance starts its networking. For more information, see [Automatic mounting fails and the instance is unresponsive](mount-troubleshooting.md#lustre-automount-fails).

1. Save the changes to the file.

Your EC2 instance is now configured to mount the Amazon FSx file system whenever it restarts.

**Note**  
In some cases, your Amazon EC2 instance might need to start regardless of the status of your mounted Amazon FSx file system. In these cases, add the `nofail` option to your file system's entry in your `/etc/fstab` file.

The fields in the line of code that you added to the `/etc/fstab` file do the following.


| Field | Description | 
| --- | --- | 
|  `file_system_dns_name@tcp:/`  |  The DNS name for your Amazon FSx file system, which identifies the file system. You can get this name from the console or programmatically from the AWS CLI or an AWS SDK.  | 
|  `mountname`  | The mount name for the file system. You can get this name from the console or programmatically from the AWS CLI using the **describe-file-systems** command or the AWS API or SDK using the `[DescribeFileSystems](https://docs.aws.amazon.com/fsx/latest/APIReference/API_DescribeFileSystems.html)` operation. | 
|  `/fsx`  |  The mount point for the Amazon FSx file system on your EC2 instance.  | 
|  `lustre`  |  The type of file system, Amazon FSx.  | 
|  `mount options`  |  Mount options for the file system, presented as a comma-separated list of the following options: [\[See the AWS documentation website for more details\]](http://docs.aws.amazon.com/fsx/latest/LustreGuide/mount-fs-auto-mount-onreboot.html)  | 
|  `x-systemd.automount,x-systemd.requires=network.service`  |  These options for non-EFA file systems ensure that the auto mounter does not run until the network connectivity is online. For Amazon Linux 2023 and Ubuntu 22.04 and higher, use the `x-systemd.requires=systemd-networkd-wait-online.service` option instead of the `x-systemd.requires=network.service` option.  | 
|  `x-systemd.automount,x-systemd.requires=configure-efa-fsx-lustre-client.service,x-systemd.after=configure-efa-fsx-lustre-client.service`  |  These options for EFA-enabled file systems ensure that the auto mounter does not run until after EFA client configuration completes.  | 
|  `0`  |  A value that indicates whether the file system should be backed up by `dump`. For Amazon FSx, this value should be `0`.  | 
|  `0`  |  A value that indicates the order in which `fsck` checks file systems at boot. For Amazon FSx file systems, this value should be `0` to indicate that `fsck` should not run at startup.  |