dd if=/dev/sdb of=/dev/sdc bs=10M 

/dev/sdb is a HDD with installed CentOS7 and able to boot.

if /dev/sdc is another HDD, the dd copy works OK, /dev/sdc can boot without problem.

if /dev/sdc is a USB disk, it can't boot after dd copy.

failed log ( when using USB disk as /dev/sdc )

dracut-initqueue[704]: calling: settle
dracut-initqueue[704]: calling: settle
dracut-initqueue[704]: calling: settle

/* log repeat and can't boot to os */

closed as too broad by Rui F Ribeiro, schily, slm Jul 19 '18 at 14:30

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.


I guess the initramfs file does not include the usb-storage driver or one of its dependencies.

You could fix this before the dd copy by doing something like:

# dracut -–add-drivers usb-storage <your initramfs file>

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