How to back up optical disk in Linux

Creating a backup of an optical disk requires generating an ISO image, a complete copy of the disk's content. You can later restore this image file to another optical disk when necessary, ensuring a dependable way to preserve your data. In Linux-based systems, you can use the dd command in the terminal to easily clone your optical disks.

Before backing up your optical disks, you need to determine the size of the optical media and verify that there is enough available space in your target location.

1. Open the terminal application on your Linux system.
2. Identify the device name of your optical drive.

   $ dmesg | egrep -i 'cdrom|dvd|cd/rw|writer'
   [    6.834672] sr 3:0:0:0: [sr0] scsi3-mmc drive: 1x/1x writer dvd-ram cd/rw xa/form2 cdda tray
   [    6.835440] cdrom: Uniform CD-ROM driver Revision: 3.20

3. Insert the optical media (Blu-ray, DVD, or CD) into the drive.
4. Determine the size of the optical media.

   $ fdisk -l /dev/sr0
   Disk /dev/sr0: 748 MiB, 784334848 bytes, 382976 sectors
   Disk model: VMware SATA CD01
   Units: sectors of 1 * 2048 = 2048 bytes
   Sector size (logical/physical): 2048 bytes / 2048 bytes
   I/O size (minimum/optimal): 2048 bytes / 2048 bytes
   Disklabel type: dos
   Disk identifier: 0x73a9f942
   
   Device     Boot   Start     End Sectors  Size Id Type
   /dev/sr0p1 *          0 1531903 1531904  2.9G  0 Empty
   /dev/sr0p2      1215132 1222619    7488 14.6M ef EFI (FAT-12/16/32)

5. Check that there is sufficient space in your target location.

   $ df -h /home/user/
   Filesystem      Size  Used Avail Use% Mounted on
   /dev/sda2        20G  5.2G   14G  28% /

6. Use the dd command to clone the optical disk to an image file.

   $ dd if=/dev/sr0 of=/home/user/cdimage.iso status=progress
   757838336 bytes (758 MB, 723 MiB) copied, 24 s, 31.6 MB/s
   1531904+0 records in
   1531904+0 records out
   784334848 bytes (784 MB, 748 MiB) copied, 24.5369 s, 32.0 MB/s

7. Verify the checksums of both the optical media and the image file.

   $ md5sum /dev/sr0 /home/user/cdimage.iso
   9a659c92b961ef46f5c0fdc04b9269a6  /dev/sr0
   9a659c92b961ef46f5c0fdc04b9269a6  /home/user/cdimage.iso