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Backing up to an external drive is an easy way to make sure you're covered in event of failure. But how should that external drive be configured?

I am a relatively new PC user and want to start backing up my hard drive. I have a 160gb external drive and my PC has two 80 gb drives configured in a raid 1 set up. The PC drive has 4 partitions on it.

Must I create the same 4 partitions on the external and back up the contents of each parton in the PC to the relevant new partition on the external?

I have a copy of Power Quest Drive Image v.7.0 which I believe will create a mirror image of the whole PC hard drive. If I used this what preparation would I need to do on the external?

First let me say good on you for setting up a backup. Sadly you're in a minority. Most people don't think about backups until it's too late.

The answer to your question depends in part on the capabilities of your backup software. But I do have some ideas and recommendations.

My experience is that most backup software will read each partition as a separate entity. You probably have different drive letters assigned to each of your partitions, and most backup software likes to deal with those "logical drives" separately even though they might reside on the same "physical drive".

But it's also very likely that your backup drive does not need to match the partitioning on the primary drive. There are times when you might want it to, which I'll explain in a minute, but more commonly the backup programs will backup everything in to single massive backup file or folder, perhaps with daily incremental additions.

Let's take my system as an example.

My entire "C:" drive is backed up once a month using Acronis TrueImage Home to a single file on my "E:" drive. "Leo-Monthly.tib" is, today, a 53 gigabyte file. Every night a new file gets generated, "Leo-Monthly##.tib" where the "##" is replaced by an increasing number. That nightly file simply contains the updates to the backup from the previous day. They vary in size from 2 to 10 gigabytes, depending on how much changed. At the end of the month, the process starts over.

The point here is that there's nothing special about the way I've partitioned my backup E drive. It's just a drive that's big enough to holding the backup files. Some really big files.

Now, other backup approaches may work differently.

Let's say that instead of using a true backup program, you run a batch file every night that simply copies the contents of your four partitions to your backup hard drive. You'll want a way to keep track of each partition on the backup drive. One way would be to create matching partitions, I suppose. But another, more flexible approach might be to simply create a single partition, and then create a sub-folder for each of the logical drives that you're backing up.

It's quite possible that some backup programs might well work in a similar way.

The one case where you might want to set up identical partitions is if you expect to be able to swap the backup drive in as the primary if the primary fails.

"Ultimately the decision of how to best partition your backup drive depends on exactly what tools and techniques you use to backup."

Most backup software assume that you'll repair or replace a broken drive and restore your data to it from your backup copies. That means that the layout of the backup drive is fairly unimportant. However if your recovery approach is to physically swap drives, then yes, I would expect a number of additional constraints would have to be met, partition layout being only one of them. This is an approach I recommend only for advanced folks.

Imaging software that you mention is another approach. In fact, true imaging software is probably the best way to achieve that scenario where you can recover by simply swapping drives. Imaging software of this ilk should simply "do it all" - meaning that it'll take care of replicating the partitions and whatever else from one drive to another.

Not all imaging software works that way. In fact, it often works in a manner very similar to traditional backup: the image is saved to a file. That file can simply be saved on any drive that has enough room. When the time comes to restore, the image is simply placed back on to the replacement drive.

Ultimately the decision of how to best partition your backup drive depends on exactly what tools and techniques you use to backup. Most likely you'll need to do nothing special. I typically recommend partitioning it as a single drive. But you'll need to check the documentation associated with your backup program to be sure.

Article C3067 - June 26, 2007 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

Not what you needed?

June 29, 2007 7:22 PM

It was a great idea and most helpfull if you might let here link to download the batchfile, task or whatever script,like yours. Hmmm I bet he is thinking if...


Ken Crook
June 30, 2007 11:28 PM

Acronis TrueImage works great.

The last time something went bad with my computer it took me a week to get everything loaded, updated, and rebuilt back to the way I wanted it, I also work at a job leaving little time for such fun. So I searched around for a better backup strategy and settled on Acronis TrueImage.

I now use Acronis TrueImage to make an image of my C: drive to an external USB drive twice a month and copy any new stuff to a pen drive when needed.

Last week something went wrong with my IE browser causing it to repeatedly hang, needing to cancel the process to clear things up. Scans with Norton AntiVirus, Windows Defender, and LavaSoft Adware-2007 found nothing. I finally had to give up and fix it.

Using Acronis TrueImage to restore the entire C: drive from the last image backup, and downloading the needed Windows updates took me about ONE HOUR!

A True Believer

May 20, 2009 8:22 PM

Just aquired a 250GB external backup drive. How do I partition it so I can backup two other laptops in their own "drive"?

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