USB Hard drive fails to mount on Raspberry Pi Raspbian

USB HDD fails to mount on Raspberry Pi Raspbian

I experienced an issue that the USB HDD does not mount or even properly show up on a Raspberry Pi Raspbian setup. Here are some tests that you can do to locate your issue, should you experience something similar.

NOTE: I did not manage to fix this! I assume the root cause is the lack of power by the power supply.

1. Power up your Raspberry Pi
2. Make sure your OS is up to date:
- apt-get update
- apt-get upgrade
3. Plug in your USB drive
4. Check if it is mounting OK:
- dmesg | grep sd

[    3.923694] sd 0:0:0:0: Attached scsi generic sg0 type 0
[   13.903099] sd 0:0:0:0: [sda] Spinning up disk...
[  128.026802] sd 0:0:0:0: [sda] Read Capacity(10) failed: Result: hostbyte=0x00 driverbyte=0x08
[  128.026838] sd 0:0:0:0: [sda] Sense Key : 0x2 [current]
[  128.026858] sd 0:0:0:0: [sda] ASC=0x4 ASCQ=0x1
[  130.027739] sd 0:0:0:0: [sda] Test WP failed, assume Write Enabled
[  132.028683] sd 0:0:0:0: [sda] Asking for cache data failed
[  132.028720] sd 0:0:0:0: [sda] Assuming drive cache: write through
[  140.032309] sd 0:0:0:0: [sda] Spinning up disk...
[  412.088806] sd 0:0:0:0: timing out command, waited 180s
[  592.099685] sd 0:0:0:0: timing out command, waited 180s
[  671.669394] sd 0:0:0:0: [sda] Read Capacity(10) failed: Result: hostbyte=0x01 driverbyte=0x00
[  671.669426] sd 0:0:0:0: [sda] Sense not available.
[  671.669689] sd 0:0:0:0: [sda] Attached SCSI disk

You can see "[sda] Spinning up disk..." If there is no successful message afterwards (here it states timeouts), it is safe to say that your USB HDD is not working as expected.

Here are some (or a combination of) options, that might fix this issue:

a) Check your power supply. It should have lots of amps (not sure what the guide line is. But 2A sounds ok)
b) Use a POWERED USB hub
c) Enable higher currents on the USB port:
- nano /boot/config.txt
- #Add this line to the file: max_usb_current=1
- #save and reboot

If you are lucky, this should have fixed your USB HDD issue.

You can verify it by running fdisk -l. The HDD should how up there now. Or run
- cat /proc/partitions