Can I backup to an internal drive?

Backing up to the same drive

Before I discuss your scenario, let's look at the scenario that makes the most knowledgeable techies cringe: backing up to the same drive.

For example, let's say you back up your documents folder to another documents folder elsewhere on the same drive - maybe the contents of C:\Users\You\Documents gets backed up to C:\Backups.

Pros (what this protects you from):

• Accidentally erasing, modifying, corrupting or otherwise damaging your documents. You can simply restore them from the backup copy.

Cons (what this does not protect you from):

• Hardware failure. If your single hard-disk drive dies, you lose everything on it, including your backups.

• System failure. When using this approach, it's difficult (if not impossible) to actually back up your entire system. If your Windows installation fails for any reason, this is not an approach that will allow you to simply revert to a backup copy.

• Malware. If viruses or other forms of malware corrupt your system, your files or even entire drives - both the original and backup copy on the same drive - would be at risk.

• Theft, fire, tornadoes, earthquakes, and the like.

Backing up to an external drive

This is a very commonly recommended approach. In fact, it's what I often tell people: "Get an external drive and some backup software and make sure that your system is getting backed up regularly".

Pros:

• You're protected from accidentally erasing, modifying, corrupting or otherwise damaging your documents. You can simply restore them from the backup copy.

• You're protected from hardware failure. If your system hard-disk drive dies, you simply replace it and restore from the backup. (If the backup hard drive dies, you replace it and resume backing up.)

• You're protected from most system failures. If you configure a complete system/image backup of your system drive to your external drive, then you can revert to a backup copy rather than having to reinstall Windows from scratch should your Windows installation fail for any reason.

• You're protected against most malware. Recovering from a malware infestation would involve simply restoring from a full system backup taken prior to the infestation.

Cons:

• Some malware can infect all connected drives, so your backup drive (and possibly your backup system) could still be infected.

• You're not protected against theft or disasters that would take out all of the computer-related equipment in your home.

All in all, it's a pretty reasonable list - that's a long list of pros without too many cons.

Backing up to an internal drive

Important: We're talking about backing up to a second physically distinct drive. Backing up to a different partition that resides on the same drive is not what I'm discussing, as it is exactly like backing up to the same drive, as mentioned above.

The only basic difference between backing up to a second internal drive versus an external drive is the connection and the location of the drive. Pretty much all of the pros and cons of the external scenario still apply.

There are a few subtle differences:

• The internal drive will be faster. Thus, it's more likely to get used for day-to-day things as well as backups. How that day-to-day usage impacts the backups will vary; typically, the impact is disk space. In addition, some alternate means of backing up that data needs to be considered.

• An external drive is typically more electrically isolated from system; this means that certain types of PC power supply or other electrical failures that might damage an internal drive might not damage an external drive.

• An external drive is quickly and easily replaced, making it easy to upgrade or swap out as needed. Unfortunately, it also often makes the external drive easier to steal.

Short summary: Backing up to a second internal drive is a surprisingly reasonable choice and shares most of the same characteristics as backing up to an external drive. Some of the differences boil down to convenience.

Backing up to offline media

Offline media - typically CDs and DVDs, but this might also include flash media - have been a common form of backup for a while.

The single biggest "pro" to most of these backup destinations is that they are either write-once media and cannot be modified after the backup is complete or they're disconnected from the computer after the backup so that they're not impacted by any subsequent failures on that machine.

Of course, the "con" is that they're now relatively small compared to the amount of data that we typically want to backup. Backing up of anything large, particularly a complete system, so far exceeds the capacity of individual media that trying to do so becomes unwieldy.

Online backup

In many ways, online backups have the promise of being the holy grail of backups. They protect what's backed up from almost everything practically imaginable.

With one huge "con" - which is a fatal flaw, in my opinion.

Like backing up to individual media like CDs or DVDs, the amount of data that would need to be backed up for a full system backup is so huge as to make online backups totally impractical for full backups. A complete system backup would take days, if not weeks, to upload to an online solution.

Unless you can upload a terabyte in an hour (just over 2.4 Gbit/s, sustained), online backups are best used to backup important data but cannot be used to back up your system.

Backup!

As you might imagine, backing up in any form is better than not backing up at all. Exactly how you should back up depends on your abilities and your needs.

One of the reasons that folks such as myself often recommend an external drive and backup software is because it's easy to set up and it gets you significant backup coverage from the most common disasters (hard drive failures and most malware).

And, if it's easy, then more people are likely to do it.

Backing up to a second internal drive could well be a worthwhile approach as long as you understand what is and is not being protected as a result.