I have an Ubuntu 18.04 installed on a 2 TB Seagate drive.

I have another 2 TB Western Digital drive formatted ext4.

I would like to copy the Ubuntu OS on the seagate drive (sda) to the Western Digital drive (sdb).

Every so often I can boot to the western digital drive and run updates and all that.

The western digital will be a backup drive.

With 2 different drives I did not think anything would have to be changed but then I read something about the UUID. I read I would have to unplug the Western Digital drive because of the UUID??? I do not want to have to plug in and unplug a drive depending of the drives usage.

I understand I can use dd to copy drive sda to sdb.

I am asking whether I have to change something, the UUID or something like that, to be able to boot to the new OS on drive sdb.

How do I change the UUID or whatever it is I need to change? Thanks for your help!

  • 2
    Instead of copying the partition with dd, you could use rsync to copy the content. This also alows you to only copy changes at second and following backups.
    – Soren A
    Jun 28, 2019 at 13:28
  • thank you, however you never answered a very important question, what is it that ihave to change??? uuid, duiu, iudu
    – Cougar
    Jun 28, 2019 at 16:21
  • 1
    @Cougar Comments aren't answers. If they intended to answer your question they would gave pisted an answer but instead they judt comnented a suggestion.
    – user880592
    Jun 28, 2019 at 17:21
  • 1
    did not know that, thank you!
    – Cougar
    Jun 28, 2019 at 17:44
  • 4
    Possible duplicate of Comparison of backup tools and also have a look here and here
    – Fabby
    Jul 6, 2019 at 10:41

1 Answer 1


I would suggest you do the following:

  1. Do a fresh install of Ubuntu 18.04 on the WD disk. You can use the same user name and password.
  2. Boot to the Seagate disk and update grub. You should then be able to choose either disk to boot which ever one is first in your boot order.
  3. As you describe periodically boot the WD disk and perform updates and install any new applications that are important to you.

I would further suggest installing a cloud service like spideroak or Dropbox to synchronise your home directory.

It is more conventional (and probably less time consuming and confusing) to use one disk for the system and one for regular backups so that if you have a problem you roll back to the last backup.

  • Thank you for replying, that is exactly what I did!
    – Cougar
    Jul 1, 2019 at 7:01

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