> For the complete documentation index, see [llms.txt](https://docs.jcore.io/clarity-gateway/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.jcore.io/clarity-gateway/installation/readme/adding-usb-storage.md).

# Adding USB Storage

You can add extra disk storage to an Iron Pi using an off-the-shelf USB flash disk or external hard drive. However, mapping the storage into your environment takes a few manual steps.

Start by plugging the USB disk into one of the Iron Pi's USB ports. Run the `lsblk` command to see the raw disk. In the example below, the USB disk is listed as `sda`, and the detected capacity if 14.3GB. It's normal for the detected capacity to be a bit below the drive's nominal capacity.

The disk has one partition, `sda1`. We will use that partition name in the next step when creating the filesystem.

![](/files/UpP7qVRFHTym09lbTOVJ)

{% hint style="warning" %}
`mmcblk0` is the Iron Pi's built-in flash drive. Do not try to format `mmcblk0` as an external disk!
{% endhint %}

### Choosing a Filesystem Type

If you want to use the USB drive to move files between the Iron Pi and a Windows or Mac computer, you should stick with a FAT32 filesystem, which is how most USB flash drives come formatted from the factory. If you want to use FAT32, you can skip the ext4 filesystem creation step below.

### Creating a Linux `ext4` filesystem

If you want to use the USB drive to run applications on the Iron Pi, it's best to format it with a native Linux filesystem.

To create a Linux filesystem on your USB disk, run:

`sudo mkfs -t ext4 <PARTITION>`

In this example, our partition is /dev/sda1, so our command would be:

`sudo mkfs -t ext4 /dev/sda1`

![](/files/Vfhjby6rLooDm2dRk4n8)

### Creating a filesystem mount point

To access an external drive in Linux, you need to mount the disk, which means attaching it to the operating system's logical file tree.

The `/mnt` directory is a common place to mount external drives. In this example, we'll create a directory called `/mnt/usb` and mount the USB drive there.

`sudo mkdir -p /mnt/usb`

### Mounting the filesystem via the command line

Once we've created the mount point, let's try mounting the filesystem to it. The command to do that is:

`sudo mount <PARTITION> <MOUNT POINT>`

In this example, our command would be:

`sudo mount /dev/sda1 /mnt/usb`

After mounting the disk, run the `df -h` command to check that it's properly attached. In the example below, you can see that `/dev/sda1` is mounted to `/mnt/usb` and has a capacity of 14GB.

![](/files/pkqCFgvrkKOHXGAzgA4f)

### Configuring the disk to mount on boot

If you want the disk to automatically mount each time the device boots, you will need to add an entry to the /etc/fstab file. Run `sudo nano /etc/fstab` to edit that file.

In the editor, add a line with the following contents:

`<PARTITION> <MOUNT POINT> <FILESYSTEM TYPE> defaults 0 2`

Put a tab beween each field. In this example, our entry is:

`/dev/sda1 /mnt/usb ext4 defaults 0 2`

![](/files/FX2kIw7QrTMRx9JZtSTr)

Type `ctrl-X` to save and exit. Run `sudo reboot` to reboot the device, and then run `df -h` after rebooting to ensure that your disk mounted correctly.