Mounting your Amazon FSx file system automatically - FSx for Lustre

Mounting your Amazon FSx file system automatically

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

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.


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 in the Getting Started exercise.

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.

  2. 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 API operation.

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

    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.

  3. Save the changes to the file.

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


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


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.


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 operation.


The mount point for the Amazon FSx file system on your EC2 instance.


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:

  • defaults – This value tells the operating system to use the default mount options. You can list the default mount options after the file system has been mounted by viewing the output of the mount command.

  • relatime – This option maintains atime (inode access times) data, but not for each time that a file is accessed. With this option enabled, atime data is written to disk only if the file has been modified since the atime data was last updated (mtime), or if the file was last accessed more than a certain amount of time ago (one day by default). If you want to turn off inode access time updates, use the noatime mount option instead.

  • flock – mounts your file system with file locking enabled. If you don't want file locking enabled, use the noflock mount option instead.

  • _netdev – The value tells the operating system that the file system resides on a device that requires network access. This option prevents the instance from mounting the file system until the network has been enabled on the client.


These options ensure that the auto mounter does not run until the network connectivity is online.


For Amazon Linux 2023 and Ubuntu 22.04, use the x-systemd.requires=systemd-networkd-wait-online.service option instead of the x-systemd.requires=network.service option.


A value that indicates whether the file system should be backed up by dump. For Amazon FSx, this value should be 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.