Can't I just copy everything instead of using a backup program?

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Summary: It's tempting to just use file copy tools to backup what you think you need. But if you're not careful, you could easily miss something very important.

The short answer is that you can, and it certainly provides a level of protection.

But.

There are definitely things that you're missing; things that a managed backup would catch and backup for you. Things that you'll really care about should the worst happen.

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To be clear, the scenario here is that you're attempting to backup C: by copying all of it to another drive, like D:. In Windows Command Prompt terms, it might be something like this:

C:\> xcopy /e /h c:\ d:\

There may be other options that would make sense, but I've included the important ones to copy the contents of all files and folders underneath the start point and copy hidden and system files as well.

In theory it seems simple, and in many ways it's fairly close in concept at least to what a backup program actually does.

But there are some important things missing. There are files that will not be backed up by this approach: most importantly would be files that are in use at the time of the copy. And some files are always in use no matter what you do.

For example a simple file copy will not backup the Windows registry because if Windows is running, the operating system keeps the files that contain the registry open and locked from outside access. So if your hard drive were to die, even if you've backed up everything else on your machine, without the registry you're looking at a full reinstall of Windows onto a new or repaired drive in order to recover.

The registry is just the most obvious and easiest example, but it's actually just the tip of the iceberg. Windows may have other files open that you can't backup with a simple copy and other applications you may be running could be doing the same.

A true backup program, however, will typically install components or use additional techniques to gain access to the protected files. In other words, a backup program will backup everything that a simple file copy cannot.

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There are a couple of other benefits to using a backup program that aren't quite as critical but still very handy.

I personally find them easy to "set and forget". Meaning that once configured, most are designed to simply run in an automated fashion. Depending on where you're backing up, it's likely you don't have to waste much energy thinking about your backups on a regular basis - they just happen.

But there's an interesting scenario where a backup program can save the day that doesn't involve a hard disk crash or other catastrophic failure.

Let's say that on day one you create an important file, and that night your "file copy" backup places it on your backup drive. On day two you make some changes to the file - perhaps deleting a section that you figured you no longer needed. At the end of day two your backup once again copies the updated file to your backup drive.

On day three you realize the changes you made the day before were a huge mistake. Ideally what you want is the copy of the file at the end of day one, before you deleted everything. Unfortunately even your backup no longer has that, as it dutifully overwrote the backup with the results of day two's work.

Backup programs almost always include a feature known as "incremental backup". Each night they back up only those things that changed, and track that separately.

I'll use myself as an example: on the first of every month, my backup program takes a complete snapshot of my entire C: drive. Each day thereafter it saves the changes that happened since the previous day's backup. For example, on the 2nd only files that changed since the 1st are backed up. On the 3rd, only files that changed since the 2nd are backed up, and so on. Each such incremental backup is tracked and stored separately. On my machine the full backup is about 45 gigabytes, but each day's incremental varies between 2 and 6, depending on how busy I was on a particular day.

At the end of the month I have the complete snapshot of the 1st as a starting point and around 30 of these collections of incremental changes from each day to the next.

The downside is that if, on the 30th, I need to restore my hard disk to its most recent backup then the restore software needs to start with the full image of the 1st, and then apply each incremental change from 2nd through the 30th in turn. Fortunately that only happens on a full restore.

The huge upside from my perspective is this: if on the 30th I decide I need a copy of a particular file as it was on the 15th, I can simply use the recovery tool to only apply the changes through the 15th and pick up that file as it was on that day.

Now, aside from the files in use that I talked about earlier, you could probably devise a system using batch files and copy operations to mimic all this. In fact that's pretty close to what I did for a long time. But let me tell you, a backup program that does this as its job is much more reliable, easier to use, and in my opinion, worth every penny.

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To be fair there are some scenarios where simple file copy works and works well enough.

For example I have a couple of drives that contain only data, and no files are in use in the middle of the night when my backup scripts run. So I do indeed mirror those drives to other drives each night using a simple file copy operation. There's no need to set up a more sophisticated backup from my needs. And rather than being in a potentially proprietary backup format, the mirrored backup drive is simple there, on-line and ready to be used at any times.

Copying files to backup can also be a space saver, under two conditions:

• You know - and I mean know - what files should be backed up and which ones you don't need to, because...

• You plan on reinstalling your operating system and applications in the case of a catastrophic failure.

In all honesty, most of my machines are in this situation - only my primary desktop is under management of a backup program. If the hard disk on my laptop were to die, for example, I would have to reinstall everything from scratch.

The important point is that this is a conscious choice I'm making. In my case the data I care about that might be on that laptop is backed up by file copies - to the desktop. And reinstalling everything from scratch is something I do periodically anyway. A catastrophic failure simple forces the schedule of when the reinstall happens.

But it's important to realize that for many people a complete reinstall would be a couple of days of lost work that a backup program could have taken care of in an hour or so.

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And that actually brings me to my final point about using copy operations as backups: restoration.

As we've seen a "reverse copy" of the original example, of D:\ back to C:\ would not restore your system. Certain critical files such as the registry would be missing. Your "restored" drive won't boot.

If your intent is to backup everything so that in the case of a failure you can simply and quickly restore everything, then a backup program is really the only way to go.

Related:

• Ask Leo! - What backup program should I use?

• Ask Leo! - So what should I backup?

Article 11761 | Posted August 16, 2007