# Filesystem and partitions

## AuterionOS partitions

| Mount point   | Persistent (reboot/update) | Size  | Mount option | Description                                                                                                                                      |
| ------------- | -------------------------- | ----- | ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------ |
| `/`           | Yes/No                     | 3GB   | ReadOnly     | Root FS, can be mounted RW ([learn more](/hardware-integration/auterion-developer-tools.md#root-filesystem-mount-option)). Wiped at each update. |
| `/tmp`        | No/No                      | 1.5GB | ReadWrite    | Temporary filesystem                                                                                                                             |
| `/var`        | Yes/No                     | 4GB   | ReadWrite    | Var filesystem. Wiped at each update.                                                                                                            |
| `/persistent` | Yes/Yes                    | 500MB | ReadWrite    | eMMC persistent storage                                                                                                                          |
| `/data`       | Yes/Yes                    | 32GB  | ReadWrite    | SDCard storage                                                                                                                                   |

## Change root/auterion user password

By default the password for root and auterion user is `auterion`. You can change it by ssh-ing into your device and run the following command `passwd`. Your new password will be persisted across reboots and updates. Keep in mind that your password can be overwritten by an update if the artifact has been repackaged with the password option.

## Root filesystem mount option

By default the root filesystem is mounted as ReadOnly for security reasons. You can re-mount it as ReadWrite with the following command but note that if you power cycle or reboot your device, the root filesystem will be automatically remounted as ReadOnly.

```sh
# Mount Root FS as ReadWrite
mountrw

# Mount Root FS as ReadOnly
mountro
```

In case you want to persist your choice, you can use the following command:

```sh
# Mount Root FS as ReadWrite
ao-root-rw.sh

# Mount Root FS as ReadOnly
ao-root-ro.sh
```

{% hint style="info" %}
The effect of the two shell scripts mentioned above will reset after an update.
{% endhint %}


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