6 Examples of DD commands to back up a Linux system

The loss of data loss is quite expensive. The loss of critical data can impact businesses of all sizes. There are several ways to back up Linux systems, including Rsync and Rsnapshot. This article provides 6 instances of backing up a Linux system using the DD command. DD is a powerful UNIX tool that is guided by the makefile of the Linux kernel and can also be used to replicate data.

Example 1: Backing up an entire hard disk
Use the DD command to back up the entire hard disk. In this example, the device name of the source hard disk is/DEV/SDA, and the device name of the target hard disk is/DEV/SDB. Execute the DD command to back up the entire hard disk/dev/sha to another hard disk/dev/sdb of the same system. As shown below:

[[email protected] ~]# DD IF=/DEV/SDA of=/dev/sdb-"If" followed by the input file, "of" followed by the output file. -Any errors during the execution of the above command will fail. However, if the parameter "conv= noerror" is added, it will continue to replicate even if there is an error during execution. -Input files and output files must be checked repeatedly before execution, and if they are reversed in order, you may lose all data. 

When backing up the entire hard drive, we can also add the sync parameter to synchronize I/O. As shown below:

[[email protected] ~]# DD IF=/DEV/SDA of=/dev/sdb Conv=noerror,sync

Example 2: Creating an image of a hard disk
Use the DD command to create an image file for your hard disk and save it on a different storage device. There are many benefits to this backup approach: ease of use, and faster backup than other methods, and faster recovery of your data.
Create an image command for a hard disk/DEV/SDA:

[email protected] ~]# DD IF=/DEV/SDA of=~/sdadisk.img

Example 3: Recovering hard disk image File recovery data
Use the DD command to restore the hard disk's image file to another hard disk. As shown below:

[email protected] ~]# DD if=sdadisk.img of=/dev/sdb

The sdadisk.img file is an image of/DEV/SDA, so the above command restores the/dev/had image to/dev/sdb

Example 4: Creating a floppy image
Use the DD command to create an image backup of the floppy disk. Enter the file to fill in the location of the floppy disk drive device, and the output file to write the floppy image file name as shown below.

[email protected] ~]# DD if=/dev/fd0 of=myfloppy.img

Example 5: Backing up a partition
Use the DD command to back up the hard disk partition. Enter the file to fill in the partition's device name, and the output file to fill in the target path or image file you specified. The DD command example shows the following:

[email protected] ~]# DD if=/dev/sda1 of=~/partition1.img

Example 6: Disc backup
The DD command allows us to create the ISO file for the source file, so we can insert the CD and enter the DD command to create the ISO file contents of a CD.

[[email protected] ~]# DD if=/dev/cdrom of=tgsservice.iso bs=2048

The DD command reads a block from the input and writes it to the output file. You can specify the block size of the input and output files. The parameter "BS" specifies the block size of the input and output files. The above DD command uses a block size of 2048 bytes.
Note: If the disc is mounted automatically, it is best to umount out before creating an ISO image with the DD command to avoid unnecessary access to the CD ROM.

6 Examples of DD commands for backing up a Linux system