External HD

March 2021

Raspberry Pi Documentation - ConfigurationRaspberry_Pi

You can connect your external hard disk, SSD, or USB stick to any of the USB ports on the Raspberry Pi, and mount the file system to access the data stored on it.

By default, your Raspberry Pi automatically mounts some of the popular file systems such as FAT, NTFS, and HFS+ at the /media/pi/<HARD-DRIVE-LABEL> location.

To set up your storage device so that it always mounts to a specific location of your choice, you must mount it manually.

Mounting a storage device

You can mount your storage device at a specific folder location. It is conventional to do this within the /mnt folder, for example /mnt/mydisk. Note that the folder must be empty.

1. Plug the storage device into a USB port on the Raspberry Pi.

2. List all the disk partitions on the Pi using the following command:

   sudo lsblk -o UUID,NAME,FSTYPE,SIZE,MOUNTPOINT,LABEL,MODEL

   The Raspberry Pi uses mount points / and /boot. Your storage device will show up in this list, along with any other connected storage.

3. Use the SIZE, LABEL, and MODEL columns to identify the name of the disk partition that points to your storage device. For example, sda1.

4. The FSTYPE column contains the filesystem type. If your storage device uses an exFAT file system, install the exFAT driver:

   sudo apt update
   sudo apt install exfat-fuse

5. If your storage device uses an NTFS file system, you will have read-only access to it. If you want to write to the device, you can install the ntfs-3g driver:

   sudo apt update
   sudo apt install ntfs-3g

6. Run the following command to get the location of the disk partition:

   sudo blkid

   For example, /dev/sda1.

7. Create a target folder to be the mount point of the storage device. The mount point name used in this case is mydisk. You can specify a name of your choice:

   sudo mkdir /mnt/mydisk

8. Mount the storage device at the mount point you created:

   sudo mount /dev/sda1 /mnt/mydisk

9. Verify that the storage device is mounted successfully by listing the contents:

   ls /mnt/mydisk

Setting up automatic mounting

You can modify the fstab file to define the location where the storage device will be automatically mounted when the Raspberry Pi starts up. In the fstab file, the disk partition is identified by the universally unique identifier (UUID).

1. Get the UUID of the disk partition:

   sudo blkid

2. Find the disk partition from the list and note the UUID. For example, 5C24-1453.

3. Open the fstab file using a command line editor such as nano:

   sudo nano /etc/fstab

4. Add the following line in the fstab file:

   UUID=5C24-1453 /mnt/mydisk fstype defaults,auto,users,rw,nofail 0 0

   Replace fstype with the type of your file system, which you found in step 2 of 'Mounting a storage device' above, for example: ntfs.

5. If the filesystem type is FAT or NTFS, add ,umask=000 immediately after nofail - this will allow all users full read/write access to every file on the storage device.

Now that you have set an entry in fstab, you can start up your Raspberry Pi with or without the storage device attached. Before you unplug the device you must either shut down the Pi, or manually unmount it using the steps in 'Unmounting a storage device' below.

Note: if you do not have the storage device attached when the Pi starts, the Pi will take an extra 90 seconds to start up. You can shorten this by adding ,x-systemd.device-timeout=30 immediately after nofail in step 4. This will change the timeout to 30 seconds, meaning the system will only wait 30 seconds before giving up trying to mount the disk.

For more information on each Linux command, refer to the specific manual page using the man command. For example, man fstab.

Unmounting a storage device

When the Raspberry Pi shuts down, the system takes care of unmounting the storage device so that it is safe to unplug it. If you want to manually unmount a device, you can use the following command:

sudo umount /mnt/mydisk

If you receive an error that the 'target is busy', this means that the storage device was not unmounted. If no error was displayed, you can now safely unplug the device.

Dealing with 'target is busy'

The 'target is busy' message means there are files on the storage device that are in use by a program. To close the files, use the following procedure.

1. Close any program which has open files on the storage device.

2. If you have a terminal open, make sure that you are not in the folder where the storage device is mounted, or in a sub-folder of it.

3. If you are still unable to unmount the storage device, you can use the lsof tool to check which program has files open on the device. You need to first install lsof using apt:

   sudo apt update
   sudo apt install lsof

   To use lsof:

   lsof /mnt/mydisk