Master Linux Backups with dd: 6 Practical Examples

Example 1: Backup an entire disk

Use dd to copy the whole source disk (/dev/sda) to another disk (/dev/sdb). The basic command is: # dd if=/dev/sda of=/dev/sdb Adding conv=noerror lets the copy continue despite read errors, and sync pads each block to keep data aligned.

# dd if=/dev/sda of=/dev/sdb conv=noerror,sync

Example 2: Create a disk image

Generate an image file of a disk and store it on another storage device. This method is fast and easy to restore later.

# dd if=/dev/sda of=sdadisk.img

Example 3: Restore a disk image

Write a previously created image file back to a disk, effectively restoring its contents.

# dd if=sdadisk.img of=/dev/sdb

Example 4: Create a floppy image

Back up a floppy disk by creating an image file. Specify the floppy device as the input and the desired image filename as the output.

# dd if=/dev/sda1 of=~/partition1.img

Example 5: Backup a partition

Copy a specific partition to an image file, which can later be used for restoration or cloning.

# dd if=/dev/sda1 of=~/partition1.img

Example 6: Create a CD ISO image

Use dd to create an ISO file from a CD-ROM. The block size is set to 2048 bytes, which matches the standard CD sector size. # dd if=/dev/cdrom of=tgsservice.iso bs=2048 Before creating the ISO, ensure the CD is unmounted to avoid unnecessary access.