The Home PC Backup – Disk Images vs File-Level Backups

July 1, 2010DavidBackup0

Backing up your PC is one of the few critical chores (yes, it’s a chore) that you must do in order to keep your data safe and your peace of mind.  Before we get into the checklist, some quick background is needed.  Generally speaking there are two types of backup procedures:  a disk image backup and a file-level backup.

Disk Images

A disk image is basically one big file that copies the exact state of your computer to an external hard drive or another source (the Mac’s Time Machine is a great example of a disk imaging program), so that if you have a catastrophic hardware failure or a severe data loss, you can reinstall your operating system and then reload the image to restore your system to the way it was — prior to the problem that necessitated the restore.  There are many programs out there that create and restore disk images, and because these programs do capture your entire drive, you don’t need to worry that something will be missed. There are two major disadvantages of disk imaging systems, however.

1. Disk imaging systems don’t always allow you to restore individual files.  Say you are writing an essay and you make a mistake and want to go back to last week’s version.  Because most disk imaging programs won’t allow you to restore the single file, in order to get the old version of the essay back, you’d need to restore your entire system to the state is was in when you last made an image.

2. Disk imaging is often non-transferrable.  Say you have an old computer and you want to get a new machine.  Disk images are generally tied to the original machine, so if you have an image of your old computer, you will probably not be able to restore it to the new one.

File-Level Backups

A file-level backup is a backup where you backup the individual files that you need for your day-to-day use. For example, in a file level backup you’d backup your My Documents folder.  So if you are working on the essay in the example above, and you want to go back to a version that’s a week old, then you can go back to your file-level backup and pull out the individual file that you need.  Now of course it would depend upon when you last backed up the essay, and if you saved individual versions, but the concept here is that file-level backups allow you to pull out individual files where disk images often do not.

The main concern about file-level backups is that they do not backup the state of your computer and they do not backup your applications.  The reason for this is that even if you did backup your program files, programs need to be installed on individual computers and therefore cannot be moved.  You cannot copy your Microsoft Office folder from your old computer and place it on your new computer and expect Office to run.  Instead, you’d need to get the new machine and use the Microsoft Office install DVD to reinstall the program on your new machine.  As a guide for file backups,  I have created a helpful checklist that will answer the question, “What files should I backup?”.

What’s the Best Method?
The best method combines a disk image backup with a file-level backup. A good rule of thumb is to make weekly images of your machine, and daily backups of your frequently used data. This way, if you do have a problem where Windows won’t start or the system becomes unusable, you can first restore your disk image – which will bring your system to the functioning state is was in when you made the backup. Then, you can restore yesterday’s data to bring everything back as close to the way it was before you had the problem.

Also note that if you are planning on moving to a new machine, you must make some kind of file-level backup so you can easily move your data from the old machine to the new machine.

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