When cloning a drive (using dd), will the UUID's for each partition change, or are they hardware specific? or does cloning it preserve the UUID as well?
What happen if a system detected two devices with the same UUID?
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Matt Clark
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Why not just try it yourself and see if they change? – Ƭᴇcʜιᴇ007 Feb 20 '14 at 18:34
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32gb USB to USB across a VM.... :'( – Matt Clark Feb 20 '14 at 18:41
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If you just want to test if DD changes UUID's or not, then why not just use a small test source disk/partition with little data on it, locally? – Ƭᴇcʜιᴇ007 Feb 20 '14 at 18:43
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And the last part is still valid. If the UUID stays the same, how the the system deal with multiple of the same UUID? I guess that works... – Matt Clark Feb 20 '14 at 18:44
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1Related: http://askubuntu.com/questions/156063/why-cant-mint-boot-my-cloned-ubuntu-partition-uuid-issue – Ƭᴇcʜιᴇ007 Feb 20 '14 at 18:46
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I failed to find this in my initial search. Found my answer, and I appreciate the help. – Matt Clark Feb 20 '14 at 18:48
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UUIDs are not hardware-specific but stored in the partition's filesystem. That means cloning a disk or partition with dd will result in the same UUID.
You can assign a new UUID by using:
tune2fs -U random <device>(ext2/ext3/ext4)xfs_admin -U generate <device>(xfs)reiserfstune -u $(uuidgen) <device>(reiserfs)mkswap -U $(uuidgen) <device>(swap)
Having duplicated UUIDs doesn't necessarily lead to errors. However booting and mounting a device by UUID will become ambiguous and may lead to the wrong device being used.
scai
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1"However booting and mounting a device by UUID will become ambiguous and may lead to the wrong device being used." Yes. This can become really dangerous when a cloned disk is used as backup. You need to double check that /home is really the disk you think it is. A "backup" done in the wrong direction can wipe out data from both disks. – Eric Duminil Apr 29 '22 at 13:45