I'm trying to clone the internal hard disk of my computer. I've booted using the 16.04 Live USB image and I can see 3 disks:

/dev/sda  # Internal SSD, copy source
/dev/sdb  # Live USB
/dev/sdc  # External SSD via SATA III USB cable, copy destination

I initiate the copy using the following command:

sudo bash -c "pv /dev/sda > /dev/sdc"

But exactly 20% into the copy operation, /dev/sdc disappears and the same disk reappears as /dev/sdd. At this point the copy operation hangs (no error is reported, progress just stops). This failure is repeatable and also happens with variations of the same command using dd or cat.

The disk is 500Gb and has 10 partitions including an EFI partition, a Windows 10 installation, Ubuntu 16.04, and various manufacturer restore bits and pieces.

Why is this device change happening, and what can I do to fully clone this disk?

  • Try Clonezilla, it is designed for doing this kind of thing. – JonasCz - Reinstate Monica Jul 4 '16 at 13:51
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    have a look at dmesg or journalctl -f to see if there are error messages , it might be that your disk doesn't have enough power to sustain the writes and this is causing it to fail during the copy, once the copy fails the power requirements drop and it comes back. – Amias Jul 4 '16 at 14:03
  • @Amias, thanks, there were no error messages in any of the logs, but using a SATA connector with an additional USB cable for more power did indeed allow the copy to finish. – Ian Mackinnon Jul 4 '16 at 18:15

This is due to not having enough power for the usb storage device and can be fixed by providing more power either by mains or by a dual usb cable.

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