How Do I Restore from a Backup?

This is actually a very common question - and a very important one.

Depending on how you're backing up, and what you're backing up, there may be
some key steps you'll want to take prior to needing those backups so as to be
able to use them when the time comes.

While the specifics vary dramatically from situation to situation, the
concepts do not. I'll cover those concepts and point you to the things you need
to know before disaster strikes.

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I'll start by splitting backups into two broad category: file and image.

Restoring File Backups

File backups are just that - backups of selected files. It can be many
files, it might even be nearly all files, but it's never a backup that can be
used to restore a machine completely. The primary purpose of file-based backups
is to be able to restore or recover:

• any of those files, but only those files
• to a working system

For example: let's say you mistakenly delete, overwrite or somehow trash the
file containing your bookkeeping records. You can recover that file from a
file-based backup.

The biggest issue with recovering from a file-based backup is getting it out
of whatever storage method your backup program uses. This is where we can't
really dive into specifics, since each program might use its own.

Some programs simply copy files - literally. Restoring the file is nothing
more than locating the backup copy of the file on some storage medium, such as
the external hard disk it was backed up to, and copying it back.

More commonly backup programs create large backup archives in single files
that contain the backed up files in some compressed conglomeration. In those
cases, you'll need to run the same backup program which would then have a
restore or browse option to let you locate and extract the file or files you're
looking for. The key is that you'll need that backup program to be able to
access the contents of the backup archive. (Caveat: in most cases. Some backup
programs actually use common formats like "zip" files for their backups, so you
might be able to use other tools. Not many do, so make sure you're prepared in
any case.)

But that's all it really boils down to for restoring files from a file-based
backup: locate the backup and use the original backup programs browse
functionality to locate and extract the files you're looking for.

Restoring Image Backups

Image backups backup an image of your hard drive. (I'm lumping both
sector-based and file-system based image backups into this category, since for
the purposes of this discussion they're the same.)

There are two approaches to restoring a complete image:

• An image can be restored to a secondary hard disk on a working system. That
  means you can't restore it to the hard disk that's in use by the system
  (typically C:), but you can restore it to some other hard disk installed on the
  machine. In this case, you typically just run the backup software and use a
  restore function that it should provide.
• An image can be restored to the primary hard disk on any system by booting
  from some other media. In other words, in order to perform a complete
  restoration of your primary hard drive (again, typically C:), you have to
  boot from something else. Most image backup programs also include the
  ability to create a bootable restore disk for just this purpose.

It's that last scenario that is both the most powerful, and the most
confusing. And the thing that most people don't prepare for.

Preparation is actually fairly simple. Before you ever need your backup -
ideally when you set up your periodic backups in the first place - make sure
you have or create the restore boot disk that your backup program should
provide. Save it in a safe place so that if you ever need to perform a restore,
you'll have it ready.

Note that this is not the same as the disk containing your
actual backup. That disk is rarely bootable by itself. The bootable media is a
separate disk - often just a single CD - that you have or create once and keep
somewhere safe.

When your hard drive needs to be completely restored from the backup image
you would:

• Boot your machine from the bootable restoration media.
• Attach or locate your backed up data - perhaps by attaching the external
  hard drive you'd been backing up to.
• Run the backup program which was on the bootable media and use its restore
  function to restore data from your backup drive to the hard disk in the
  machine.

Again, conceptually simple, but it's very easy to overlook that initial
step.

What's unique about restoring an image backup is that you don't need to have
anything installed on the machine's hard drive; it can be a brand new and
completely empty hard drive. You boot from a CD, and then restore a backup
image to that new hard drive.

Restoring Files from an Image

Sometimes even with an image-based backup you just want to restore a
file.

The good news here is that almost all image-based backup programs will also
let you view the contents of an image backup and extract from it just the file
or files you need. In many ways this is just like a file-based backup. Just
fire up the backup program and use its restore or browse features to examine
the contents of one of your backups to locate and restore your file.

An image-based backup can be considered a superset of a file-based backup;
it has everything that the file-based backup has, and more. The cost? The size
of the resulting backup, and perhaps the amount of time it takes to perform
either the backup or restore.

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No article on backing up would be complete without reminding you that all of
this is moot if you're not actually backing up.

Back up.

Back up regularly, so that when the time comes you'll have some of the
options above to choose from as you successfully restore your data.