Disk Cloning, Revisited

Note: This post was updated on September 23, 2010 to correct factual errors concerning Symantec's disk imaging products.

We wrote about disk cloning (a.k.a. disk imaging) in our third Cookbook, but it's such a useful tool for libraries that it's worth revisiting the topic and sharing new developments in the field.

Moreover, many libraries, housing developments, community centers and other organizations will soon receive new computers as a result of BTOP grants approved in the public computing category. In some cases, the organization responsible for administering the grant will install an operating system and applications. In other cases, grant beneficiaries will receive clean, fresh-from-the-factory PCs or they'll decide that the pre-installed applications don't meet their needs. In both of these scenarios, a disk cloning application would save these organizations a great deal of time and effort.

Uses and Benefits of Disk Cloning Applications:

Disk cloning tools such as Norton Ghost and Acronis True Image take an exact copy of an entire hard drive, or a single partition on a drive, and copy it to another drive or a backup storage location of your choice.  Therefore, in addition to copying data, files and folders in the manner of a backup program, imaging tools copy the operating system, boot files and applications, along with all configurations and settings in place when the imaging takes place. Disk cloning has several potential applications for system administrators in libraries. For more detail on these benefits, see Disk Cloning in Libraries or the Wikipedia article on disk cloning. In brief, the applications include the following (this list isn't meant to be comprehensive):

  • Faster setup and deployment of new computers
  • Speedier software and operating system updates
  • Cleanup to ensure consistency and undo patron alterations
  • Fixing operating system and software malfunctions
  • Error forgiveness
  • File and system backups

An Evolving Technology

Like any type of software, disk cloning applications evolve continuously in response to demands from users and developer innovations. Some vendors restrict newer features to their more expensive enterprise products, so don't assume that every imaging application will include the following capabilities. 

Smart copying: Disk imaging software traditionally works by copying every sector from the target hard drive to make sure that all data is captured. Smart copying saves space by verifying that each sector actually contains data before copying it.

Hot imaging: Many organizations create disk images and store them for later deployment. However, when the administrators are ready to deploy the image to a new machine, it might be outdated, requiring that they shut down the source computer to create another image of it. Hot imaging lets administrators create an image from a running machine, which ensures that the source image is as fresh as possible.

Virtual machine support: 

With more and more organizations running enterprise applications on virtual machines, administrators need an imaging solution capable of backing up and restoring virtual machine images.

Dissimilar hardware: One constraint found in the early versions of most disk cloning applications was the need for identical hardware on source and destination machines. In other words, since cloning applications copy device driver files and other hardware-related settings from the source hard drive, images wouldn't work properly unless the destination computer had the exact same hardware configuration.  The latest versions of Ghost and other cloning applications contain features that bypass this limitation, so that administrators don't need identical computer hardware in order to use this technology.

Vendors

Symantec Ghost (once developed by Peter Norton , but now owned and maintained by Symantec) and Acronis True Image have been the best-known products in this category for quite some time. However, the List of Disk Cloning Software on Wikipedia makes it clear that there's a lot of competition from both open source projects and proprietary applications. Symantec developed Ghost for the home user market, where it competed with True Image Home and other products. For businesses, Symantec provides two imaging tools: Ghost Solution Suite and Altiris Deployment Solution. Both offer users the ability to reimage several computers at once across a network using a single reference image (a feature usually known as multicasting). Acronis and other vendors offer similar products for the enterprise market.

Conclusion: Don't take our word for it

I hope this brief overview of disk cloning software makes it sound appealing and useful, but if you're still in doubt, look over the Stories from the Field section of Disk Cloning in Libraries wherein Jarvis Sims of Hall County Library System, Michelle Foster  of Boone County Library and Matt Beckstrom of Lewis & Clark Library briefly explain their reasons for using disk cloning software. Also, check out this thread in the TechSoup Community Forum with recommendations from ten experienced nonprofit techies.