Using external storage devices

Over time, the storage on the SD card may become full. rxOS supports using external storage devices via the USB ports. Only one external storage device can be used at a time.

The following table shows the supported disk formats and their characteristics.

format integrity check large disks power failure recovery
FAT32 Yes No No
NTFS No Yes Yes
ext2 [1] Yes Yes No
ext3 [1] Yes Yes Yes
ext4 [1] Yes Yes Yes

FAT32 is the most common disk format for USB sticks and external hard drives. Although exFAT is becoming more common with large-capacity devices, it is not supported by rxOS, so such devices should be reformatted using the NTFS format (FAT32 formatting on Windows does not support large disks).

Linux users may use ext2, ext3 or ext4 format in addition to the other two.

Integrity check is prerformed on the disk where supported and an attempt is made to fix any problems with the on-disk data. While FAT32 supports integrity checking, it is not as complete as running disk checks on Windows machines.

[1](1, 2, 3) Creation of disks in this format is only supported on Linux operating systems

Connecting an extrnal storage device

External storage devices can be simply plugged into one of the available USB ports.


Some external storage devices (and especially mechanical USB hard disks) draw a lot of electrical current from the USB port and may cause Raspberry Pi to shut down. In such cases, a powered USB hub will be required.

When the storage device is plugged in, it is checked for format. If the device uses an unsupported format, it is not used and may be safely unplugged.

rxOS then mounts the disk to a temporary location to test that it can be mounted. If the test mount fails, the disk is ignored and not used as external storage.

When the test mount is successful, rxOS will mount the disk as external storage and will redirect downloads to it.

Once the disk is mounted, reindexing of the content is started, and any content that already existed on the attached disk becomes available after a while.


Although it is possible to attach more than one storage device, only the last-attached device is used as external storage. The other storage device is unmounted and may be unplugged.

Disconnecting the external storage device

External storage devices may be simply disconnected. Unmounting is done after the fact, unless the user interface provides support for unmounting.

When a disk is disconnected, downloads are redirected to the internal storage on the SD card, and reindexing is started. Any files that were present on the external storage device become unavailable afer a while.

Status LED indication

During storage hot-plug events, the status LED (green) indicates the status of the hot-plugging.

LED blinking slowly (0.5s interval) indicates that the storage mounting has started.

LED blinking fast (0.1s interval) indicates that the integrity check has started.

LED solid indicates that the storage device was mounted.

LED off indicates that the storage device was not mounted due to an error.