I wanted to connect the external USB disk to backup logs, configuration files and other critical data which are running on Raspberry Pi internal SD card.
I was trying to connect external USB HD to Raspberry Pi. Though the LED was lit, disk was not detected by Pi. I felt something wrong with the disk so for testing it, connected USB disk to laptop. Disk was detected successfully and was able to read write some files to it. After googling for a while found that the root issue was inadequate power from Pi to USB Disk.
I bought an external powered USB Transcend TS-HUB3K from the local computer shop. It worked like a charm 🙂
Now, I’ve connected two USB disks instead of one and still two more ports left to connect USB stick or any other USB device without worries about lack of power supply from Pi.