I have a 2TB 3.5" hard disk attached to a powered SATA to USB 3.0 adapter, which is connected to my Raspberry Pi 2. The Pi will boot with the drive attached and the drive will show up in
fdisk -l, but it takes ~20 seconds to do so. However, I cannot mount the drive at all. It is in EXT4 format and the main partition is at
/dev/sda2 but if I do
sudo mount -t ext4 /dev/sda2 /mnt/hdd the Pi hangs until it eventually fails to mount it, after around 5 minutes.
Is this a power issue? And if so, would a powered USB hub fix the problem?