How to Use DD to Clone a Disk to a Bigger Disk

Linux and Unix users can create an exact clone of a disk using the "dd" command from the command line. If you run out of space on a hard drive, you can clone the smaller disk to a larger disk. The "dd" command is a low-level copying and conversion tool. This means that it copies the raw data, including any unused bits on the hard drive. The "dd" command can also be used create an exact copy of a CD or DVD.

Instructions

1. Open a terminal window or log into a terminal session.

2. Type the command "df" to find the device names for the disk you want to clone and the larger, blank disk. The device names will look like: "/dev/sda" and "/dev/sdb".

3. Type the command "dd if=/dev/sda of=/dev/sdb" to clone the smaller disk to the larger disk. Replace "/dev/sda" and "/dev/sdb" with the device names that you found in Step 2. The device name for the original disk is placed after "if=" in the command. The device name of the larger disk is placed after "of=" in the command.

Tips & Warnings

• Make sure you place the device name of the original disk after the "if=" portion of the command and the device name of the new disk after the "of=" portion of the command. Otherwise, you will completely erase your original disk.

References

• Backup How To: Linux Backup: Hard Disk Clone with "dd"
• Linux Man Page: dd