| Ghost imaging, often called cloning, is a software-driven data backup process that copies the contents of a computer hard disk in a single compressed file or set of files, referred to as an image. The ghost image copies the entire contents to another server or hard disk for storage, including configuration information and applications. The software also converts a ghost image back to its original form when needed. On personal computers (PCs), ghost imaging is used to back up everything on the hard disk, often while reinstalling an operating system (OS). The purpose of the ghost image is to allow the cloning of the system onto other systems, or to enable a quick restore of a system. Ghost imaging is often used to quickly set up blocks of notebooks, tablets or servers. It enables migration from one disk or PC to another, for example, to transfer from a hard disk to a solid-state drive. How ghost imaging works Ghost imaging usually creates a disk image of the software on a computer, including systems settings and details. That image allows quick installation of a new copy. The ghost image is often compressed to save space and speed up transfers to the target system, and it may be encrypted for security. A typical cloning setup has a number of alternative images in a library. Ghost imaging tools can make hundreds of PCs as exact copies. A master machine is built, and its hard disk is imaged to a file. Then, all the other machines have that image applied, followed by a customization process that gives the installed OS its own identity. Pros and cons of ghost imaging Ghost imaging is much faster than installing each machine separately, especially if it involves installing many applications. There are different types of ghost images, depending on use case. For example, a data center supporting many mobile devices and desktops will need a tool focused on updating mobiles in batches, as well as individual restores. A cloud cluster will likely only use the imaging tools that are part of the cloud software stack. High-performance computing setups use ghosting to create images across hundreds or thousands of servers. Ghosting can save hours of setup time compared with loading programs from scratch, and it reduces errors in the process. However, updates are not incremental. When the new image replaces the OS on the destination, local user data or customization is lost. Images are tied tightly to one hardware platform. If an organization has many different target-system types, creating and managing images is difficult. Support can also be a challenge. For example, Microsoft does not support image-based cloning of installed Windows systems. Read more...
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