How to make disk image with dd on Linux or Unix

How to clone an entire hard disk

The syntax is as follow to make disk image with dd:
dd if=/dev/input/DEVICE-HERE of=/dev/OUTPUT/DEVICE-HERE bs=64K conv=noerror,sync
To clone /dev/sdc (500G) to /dev/sdd (500G) in Linux, enter:
# dd if=/dev/sdc of=/dev/sdd bs=64K conv=noerror,sync
In this example, I am going to clone /dev/ada0 (500G) to /dev/adb0 (500G) in FreeBSD and make an image using dd. For example:
# dd if=/dev/ada0 of=/dev/adb0 bs=64K conv=noerror,sync
Where,

1. if=/dev/file : Input device/file.
2. of=/dev/file : Output device/file.
3. bs=64k : Sets the block size to 64k. You can use 128k or any other value.
4. conv=noerror : Tell dd to continue operation, ignoring all read errors.
5. sync : Add input blocks with zeroes if there were any read errors, so data offsets stay in sync.

How to clone a partition and make disk image with dd

To clone /dev/sdc1 to /dev/sdd1 with dd and create an image, enter:
# dd if=/dev/sdc1 of=/dev/sdd1 bs=128K conv=noerror,sync


Making disk image with dd using live CD/DVD or USB pen drive You can boot from a live cd or USB pen drive. Once booted, make sure no partitions are mounted from the source hard drive disk. You can store disk image on an external USB disk. The syntax is as follows dd if=/dev/INPUT/DEVICE-NAME-HERE conv=sync,noerror bs=64K | gzip -c > /path/to/my-disk.image.gz In this example, create disk image for /dev/da0 i.e. cloning /dev/da0 and save in the current directory: dd if=/dev/da0 conv=sync,noerror bs=128K | gzip -c > centos-core-7.gz


How to restore system (dd image) The syntax is: gunzip -c IMAGE.HERE-GZ | dd of=/dev/OUTPUT/DEVICE-HERE For example: gunzip -c centos-core-7.gz | dd of=/dev/da0 Tip #1: Not enough disk space locally? Use the remote box You can send the image through ssh and save it on the remove box called

user: dd if=/dev/da0 conv=sync,noerror bs=128K | gzip -c | ssh user 'dd of=centos-core-7.gz' You can see status with dd command as follows: dd if=/dev/da0 conv=sync,noerror bs=128K status=progress | gzip -c | ssh user 'dd of=centos-core-7.gz' Here is how to restore image from local system: The syntax is: ssh user 'dd if=disk.img' | dd of=/dev/sdb ## OR ## ssh user 'dd if=centos-core-7.gz' | gunzip -c | dd of=/dev/sdb ## add status=progress if needed

## ssh user 'dd if=centos-core-7.gz status=progress' | gunzip -c | dd of=/dev/sdb Tip #2: See progress while making an image with dd You need to use GNU/BSD dd with coreutils version 8.24 as follows (pass the status=progress to the dd): dd if=/dev/sdc1 of=/dev/sdd1 bs=128K conv=noerror,sync status=progress

How to Make Disk Images in Linux with DD Command

Install LSSCSI Utility

Open the command-line terminal.

Make sure to have the “lsscsi” utility installed on your system. If it is not installed, try to install it using the below “apt” command followed by the keyword “install” and “lsscsi”.

sudo apt install lsscsi

After installing the “lsscsi” utility, now it’s time to use it for listing all the storage devices of our Linux system. 

$ lsscsi

Check Disk Information

$ sudo fdisk /dev/sda

Create a Clone Disk Image

Now you have almost every piece of information regarding the “/dev/sda” drive.  Press “q” to exit the commanding theme. Now, you are ready to make a disk image using the DD command.

$ sudo dd if=/dev/sda1 of=/tmp/sda.img bs=1k conv=noerror

Let’s check the destination image file to see if all the data from the source drive has been cloned into it properly or not. Use the below list command along with the path of an image file of the drive as:

The output shows the rights assigned to this image file, its size, and location. You can say that it has similar rights and size as the original disk drive have.

To see some more information regarding the disk image file, you have to try the below “fdisk” command followed by the flag “-l” as below.

Clonezilla

Clonezilla is a set of utilities that we can use to create, restore, and deploy images.

We can use Clonezilla in two ways: the Live Clonezilla distribution and the command-line tool. The process of creating and restoring the image is the same for both approaches. Therefore, we’ll go with the former.

Our Linux system is installed on the /dev/sda disk — specifically, on the /dev/sda1 partition. Our data partition is /dev/sda2, and that’s where we’ll write the image of /dev/sda1.

Creating a Bootable Clonezilla Live USB Stick

$ unzip -d clonezilla-live-12.1-amd64.zip /mnt/pendrive

Booting System Into Clonezilla Live

Creating the System Image