Disk Imaging Utilities

• There are several free programs for making disk images: dd, Partimage and Clonezilla are popular choices; only dd comes standard with all Linux systems. dd works by reading one byte of data at a time from a disk and copying it to a file. Because disk imaging utilities require raw access to disks, they should not be run while the system is up.
  
  

Creating Disk Images

• Disk images are larger than the files they represent because they store all the information from a disk and not just the data used by files. Disk images can leak confidential information because they may contain traces of deleted files. Creating a disk image is a time-consuming operation that requires a second disk on which to store the image.
  
  

Restoring Disk Images

• When a disk image is restored, all the data on the target disk gets destroyed. Because the new computer receives an exact copy of the old computer, you must carefully examine the hardware configuration in /dev and check the systemwide configuration in /etc to ensure the old configuration is appropriate on the new computer.