What’s the Difference between a Clone and an Image?
Hi everyone. I’m Leo Notenboom for askleo.com. If you're watching this online and there's a
like button, when you're done with this video, I’d really appreciate it if you hit that like
button. It's one of those things that really helps, not only me, but it helps other people
find the answers they're looking for when they're searching for videos. So, this is one of those
questions that is so common. And one of the, I’ll just call it a deep dirty dark secret,
is that not everyone agrees on the difference between a clone and an image. They use the terms
interchangeably. Some people use them to mean the opposite of what other people mean. So what
I want to do here is walk through my definition of clone and image, which of course, I believe to be,
I believe it to be the correct one. Honestly I believe it to be the more common one. And then
hopefully that will help you understand exactly why you want one and not necessarily the other.
So a clone? We'll start with a clone. A clone contains absolutely everything of a disk. So if
you clone a disk, hard disk A to hard disk B, B should be indistinguishable from A. Now you can
imagine that that's a pretty handy thing at times. For example if you're replacing a hard disk,
a quick clone of copying everything from one to another and then replacing it would seem
like a really really valid solution. And there are absolutely scenarios where it's the right thing to
do. The issue is that a clone, as I said, copies everything. And by everything I mean not only the
data that's on the disk, not only the operating system, not only the overhead information,
but it actually copies everything. In a true clone everything is in exactly the same place.
And everything that was in the free space on the old drive is copied to the new drive. So that even
the unused areas of the hard disk are, in fact, copied to the clone. In reality most of the time
you and I don't need clones. Clones come in very handy when you're doing data recovery or data
forensics, when you're actually trying to recover some of the information that might be in that free
space, or if there's something specific about the physical layout of the files that matters to you.
But for backing up, and for most common uses that you and I as average consumers might encounter,
a clone is overkill. The reason it's overkill is not only is it
copying more than it needs to, but it's going to take up more space than it needs to.
A clone of a drive is going to be about the same size as the drive regardless of how much
information is actually stored on the drive. Yeah it might be compressed, but it's always going to
be proportional to the size of the drive you're copying. An image is a copy of the “information.”
on a drive. By that I mean an image is going to look at what's stored on the drive, the files,
the folders, the overhead information, the operating system, all of that stuff, and copy only
that. The free space is left behind. The order of the files is not preserved,
which in an ideal world actually means that if you were to image a drive and then restore the image
everything would come back defragmented (depending on the backup utility you're using to do that).
But the bottom line is that an image only contains what's actually stored on the drive and that's
exactly what you need for backing up purposes. And that's all you need for backing up purposes.
Because when you restore, you come across a catastrophe where you had to replace a hard drive
or you've lost a file or whatever, it's the data that was stored on your hard drive that matters.
And it's the data that was stored on the hard drive that is backed up in an image. And it's
the data on your hard drive that is then restored when you restore that image. So as you can see
both an image and a clone contain everything. It's just that our definition of “everything.”
changes depending on what you're talking about. An image contains all of your data
everything you care about. A clone contains everything on the hard disk whether you care
about it or not. That's the difference. And when in doubt it's an image that you want.
For links related to the original article on which this video is based, for updates, for
comments and more visit askleo.com/23456. I’m Leo Notenboom. This is askleo.com thanks for watching.