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Lets say I have /dev/sda and /dev/sdb.
Before, I run dd if=/dev/sda of=/dev/sdb bs=128M, and it succeeded.

Then after some time, there is update on first disk, and I want to clone it to second disk. But I don't want to run dd from beginning, because ... well it takes time.
Any solution to update on the /dev/sdb without dd'ing from start?

UPDATE : the disk actually is ntfs, so rsync is not a solution. Also, I want the second disk to be bootable like the source disk, using rsync would break so many things.

Rinaldo Jonathan
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2 Answers2

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I bet RSync will do the job perfectly. Actually, you could also have used it to clone your disks at first instead of using dd.

Httqm
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  • the disk is ntfs. but I want solution to be as general as possible. and I want the destination disk to be bootable like the source disk, and using rsync would make different uuid, broken bootloader and things like that. – Rinaldo Jonathan May 28 '19 at 06:47
  • @RinaldoJonathan Got it ;-) You should have said this (and other details you gave in other comments) while asking your question. Can you, please, update your initial question with these constraints ? – Httqm May 28 '19 at 06:50
  • okay, will do. /15char – Rinaldo Jonathan May 28 '19 at 06:51
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You can try using blocksync, bdsync or even rsync --inplace --copy-device (if your rsync version supports it) to achieve what you ask.

Be aware that all these methods will read the entire source and destination drives, but they will transfer only changed blocks.

shodanshok
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