Comments on: dd: the ultimate disk cloning tool

By: Charles

Charles — Sat, 19 Dec 2009 23:04:40 +0000

I am duplicating my TimeMachine drive now to a larger drive. Mac users might be interested to know that the drive identifiers can be found using DiskUtility.app — click on the volume and click the Info icon. I have a lot of drives attached and found mine were disk3s1 and disk7s1. As a sanity check I did the following:

$ ls -la /dev/disk3s1
brw-rw-rw- 1 root operator 14, 10 Dec 18 00:51 /dev/disk3s1

$ ls -la /dev/disk7s1
brw-rw-rw- 1 root operator 14, 17 Dec 19 16:46 /dev/disk7s1

Note that the disk3s1 was mounted yesterday and the newer one was just plugged in today. This gave me some confidence I was doing the right thing.

Finally, I had to unmount (eject) the two drives because I got the following warnings:

$ sudo dd if=/dev/disk3s1 of=/dev/disk7s1
dd: /dev/disk3s1: Resource busy

$ sudo dd if=/dev/disk3s1 of=/dev/disk7s1
dd: /dev/disk7s1: Resource busy

The third time was a charm. I expect it to take an hour or so to complete. If something goes wrong, I’ll be back to tell you about it.

By: Russ McClay

Russ McClay — Tue, 02 Jun 2009 06:11:23 +0000

dd is a common UNIX program whose primary purpose is the low-level copying and conversion of raw data. dd is an abbreviation for “dataset definition” in IBM JCL, and the command’s syntax is meant to be reminiscent of this.

http://en.wikipedia.org/wiki/Dd_(Unix)

By: Casey

Casey — Sun, 18 Jan 2009 15:16:19 +0000

Clonezilla actually uses dd as one of it’s tools. Other tools it uses are ntfsclone for NTFS and partimage for just about everything else. The good thing about dd is that it will work regardless of file system type or if there are errors on the disk.

By: rupert

rupert — Sun, 18 Jan 2009 12:46:21 +0000

Personally, I prefer clonezilla:
http://clonezilla.org/
Just as powerfull and opensource, and is has a nice GUI to boot.

By: Dotan Cohen

Dotan Cohen — Sat, 17 Jan 2009 17:34:11 +0000

@Daniel:
I know what you mean. I often find the CLI to be both easier to use and more intuitive than GUIs for many common tasks.

By: Daniel Pataki

Daniel Pataki — Sat, 17 Jan 2009 17:31:30 +0000

Isn’t that the most awesome thing about Linux?

You search for an app, and then you realize there’s a command as “complicated” as “dd”. Totally aweomse Joe, thanks!

By: Casey

Casey — Sat, 17 Jan 2009 14:50:02 +0000

This utility was originally “convert and copy,” however the name “cc” was already taken by the c compiler, so for some reason the author decided to make it “dd,” which earned its nickname “disk dump.

By: What is Microsoft Windows?

What is Microsoft Windows? — Sat, 17 Jan 2009 13:12:45 +0000

@Paul: Yes

By: LECHIFFRE FREDERIC

LECHIFFRE FREDERIC — Sat, 17 Jan 2009 11:03:03 +0000

I think dd stands for disk dump

By: VD

VD — Sat, 17 Jan 2009 03:43:44 +0000

I always used Ghost as ist does have a boot-disk which lets you recover even without a running os. Seems to having difficulties with ntfs-partitions though (or my version is simply to old^^).

By: What is Linux?

What is Linux? — Sat, 17 Jan 2009 01:41:22 +0000

if = input file
of = output file

That makes it easier to remember. And besides the nickname, what does “dd” really stand for?

By: Paul.

Paul. — Sat, 17 Jan 2009 00:32:13 +0000

Hey Joe,do you know or those command also apply for openSUSE-11.1? And is it possible to change the command into, dd if=/dev/dvdrom of=image.iso bs=2k to write it to a dvd disk?