Drive Imaging versus Drive Cloning?
I suspect at one time there was a much more rigid technical distinction between the concepts of "Image" versus "Clone". There still may be, but I suspect that in popular usage, there is a bit more interchangeability between the two.
In general conversations I tend to refer to an "image" (noun) as being the physical data (structure/contents) copied captured off a source drive or partition. I may then apply the "image" to one or more target drives using that previously captured information. I suppose you could refer to the process of capturing the data off the source drive as "imaging" it (verb), as well as when you image (verb) apply the image to the target. Depending on the method and software used, it may be a complete image (sector by sector capture of the entire partition/drive -- whether blocks in those sectors are in use or not...good for forensics) or simply a file/folder based image that only captures files/folders/structure that are active blocks on the drive and not any "unused block" sector data.
When I refer to "cloning" a system I tend to refer to using an image to make one or more exact replicas (sector by sector) of a source drive to one or many target drives. I use "cloning" as a process description or verb form.
Regardless, the point is that what we are attempting to do is copy the system, application, data files, and structure from one hard drive. It may then be used as a backup to restore back in the case of a failure...or it may be used to replicate that data to other drives. Imaging/Cloning is a bit more expansive than a "backup" whereas an image/clone should (typically) restore an entire operating system, a backup would simple be concerned with capturing and preserving data for restoration in failure, but not necessarily the operating system itself.
(I'm open to suggestions to correct or fine-tune the distinctions as I am using them here!)
Well, most home users probably don't care. They (hopefully) have a "system restore" disk that would allow them to restore their base home pc system to its original "out of the box" state in the event of a catastrophic failure. Hopefully they have their data backed up separately as OEM system restores only put the system back, not your data. XP and Vista also have a "system restore" of sorts that attempts to restore your operating system to a previously-saved state in the event of bad-things happening. I've never used it so I can't say how effective it really is.
XP and Vista both have backup tools from Microsoft...but I'm saving that for a later "backup post."
The real folks who care about image/cloning of systems are enterprise/corporate or small-to-mid sized businesses. In these cases technicians may need to deploy hundreds to thousands of workstations at once. Imagine going to each one, putting in a setup disk and setting it up from scratch! Imaging allows us to build several "base" configurations of laptops and workstations and store that image on CD/DVD media (or USB drives and servers). Then when we have a new machine or a corrupted one, we just recover the user's data, apply the image (10 min - over an hour depending on the software/technique), reboot, tweak a few things and restore the user's data and we are gone. Usually in about one hour or less the user is back at work.
It is a real time-saver and helps ensure standard configurations on our platforms. Yes you do have some time invested in building the source machine(s) the way you want, configuring them, and running sysprep so you don't have to mess with duplicate SID's on your stations (XP or Vista). If you forget to do that, you would have to go back and use the NewSid utility to reset them....
There are a wide-variety of enterprise class ways to capture and deploy images. Some of the more popular are Symantec's Norton Ghost, Acronis True Image, and Novell's ZenWorks imaging. There are also a number of popular Linux-based products.
Freeware Imaging Solutions?
While the enterprise-class image/clone applications are very battle-tested and robust, they often carry large price-tags and can be a bit intimidating for home users (or SOHO users) to approach.
There are a number of free imaging solutions on the Net, here are just a few (in no particular order) each with their own techniques and limitations.
- Device Image
- Partition Saving
- g4u - Harddisk Image Cloning for PCs
- Synergix imageIT
- DriveImage XML
- Self Image
- Miray Software - HDClone
- Clone Maxx
- EASEUS Disk Copy
- Seagate Technology - DiscWizard
- Seagate Technology - MaxBlast 5
- Linux general usage:
- Using a Linux Live CD to clone XP - JustLinux Forums
- How to migrate XP, Vista, Linux, BSD and Solaris to a bigger hard disk - JustLinux Forums
- Other applications and resources (free/$)
I have used Ghost extensively at work to image and restore drives. It is a solid tool that works well. I have used Seagate's DiscWizard ( Hard-Drive Hell and the DiscWizards; A Six-Act Play ) to clone my system when I upgraded my personal hard drive. I've used Altiris to lay images down at work (but not create), and we are just now starting to use "Clonezilla" as a high-speed imaging tool.
Clonezilla is noteworthy solution as it is freeware/open-source and based on Linux. (Sure, many are.)
However it is fast in capturing images and very, very fast in applying images back to target drives. Why? Well, instead of doing a sector-by-sector copy of the source drive, it only captures the used blocks on the disk. Not the unused space. This saves a bunch of time.It also supports "multi-casting" the image to multiple target machines at the same time. Very handy for project size deployments. Images may be "put-back" to a target from a CD/DVD, portable USB drive, or a network share.
This is something we are doing "locally" in our shop, and our "official" enterprise image and cloning solutions remain Ghost-based for now.
However, all this might change soon....Microsoft has waded into the image waters with a free utility for all.
...and that's coming up next!