Using Clonezilla

04 May, 2023

In my post about managing your own disk drives, I described how learning more about how data is stored on your devices can give you more control. I briefly touched on cloning then.

In today's post, I want to take a look at what cloning is, and how I use a simple tool called Clonezilla to do this myself.

I won't do an attack of the clones joke

The best way to think about cloning is as a snapshot of a disk drive.¹ You can clone a data drive, but you can also clone the drive that runs your operating system. The cloned snapshot of your drive is called an image. This image is a file that you can then store elsewhere.

Cloning is the ultimate form of backup. It not only creates a mirror copy of your files and their locations, a cloned image can be an exact copy of your entire operating system and all the software installed on it at the time the cloning happened. If you did everything right, then you should be able to reverse the process; provided you are using the same or similar hardware, you can just transfer your cloned image onto a new drive, swap out, for example, a crashed drive, and on restart, the system should reappear. Of course, any changes made after the clone was created will be lost.

That is about the extent of how I use cloning. I clone my systems several times a year, and store those images onto a large HDD drive. It's fine to use slower drives for cloning, because your are only using these to store the images.

Clonezilla

There are companies that make cloning easy to do, usually for a fee. If you want full control over the process and want to be sure you are the only person handling your images, then I recommend a free and open source piece of software called Clonezilla.

A recommendation to use Clonezilla must come with a small warning. The interface looks very dated (you'll grow to love it, weirdly) and it feels very technical. There are a lot of different ways to clone data and software, and Clonezilla offers a range of options. The good news is that just pressing enter with each choice usually takes you through the easy and default path to cloning your system.

Preparations

Note: I began writing step-by-step instructions for installing and using Clonezilla, but other people have already done that, and better than I could. I will add some examples under Documents below.

You will need an 8GB (or more) USB thumb drive.

You will also need an external hard disk. It's fine to use an older HDD for this. Ideally, this disk should be larger than the hard drive you are using. Let me explain:

There are two basic types of cloning that are useful to know as a beginner:

1. You can clone directly from one hard disk to another
2. You can flash an image of your disk drive and save that image on another disk drive

Option 2 takes up less space. I store several cloned images on one external hard disk. Clonezilla will let you reverse the process when you need to use the image.

With option 1, direct disk-to-disk cloning, Clonezilla has a strange limitation, one I unfortunately learned about after I purchased my first cloning drive. The target drive has to be a little bit larger than the source drive. Keep this in mind if you want to clone directly to another disk.

Many external drives either have their own power or are essentially very large USB flash drives.

It is possible, however, to just use another SSD or HDD that is normally designed for use inside your laptop or pc. This can be quite handy in emergencies; when one drive crashes or goes corrupt in your system, you just swap in the reserved cloned system and your operating system is back. These types of drives are also cheaper than external drives.

There are two types of solutions I have found for using these internal disks. For SSDs, you can buy a simple adapter cable that will enable you to connect the SSD to a USB port on your device. For older HDDs, you can buy a kind of powered casing, mount the HDD inside and you've got a working external drive. This approach, in particular with older HDDs, can be very cost effective.

Procedure

Once you have Clonezilla on a thumbdrive, you will need to do the following:

1. Turn off your computer
2. connect the thumb drive
3. connect the external 'target' drive
4. turn the computer back on into boot mode²
5. select the thumb drive that has Clonezilla on it and start it up

What follows is a very 1990s looking interface with a lot of orange. Don't be put off by it. It helps to have a tutorial with screenshots for this part on your phone or a second laptop. See examples below.

Essentially, you can press enter going through the menus. Some tutorials recommend entering 'expert mode', but I always just use 'beginner mode'.

The main decision you'll need to make is whether to create a direct disk-to-disk clone, or create an image of your source disk. Remember, for disk-to-disk, you'll need a target (external) drive that is slightly larger than the source.

The bit where you need to pay close attention

What you do need to pay close attention to is selecting the source and target drives. If you do that the wrong way around, then you will wipe your operating system, and be left with two empty drives. I usually use the sizes of the drives to help me figure out which is which, but brand names and other identifiers will be shown too.³

If you want to know the exact full names of your drives, just to be sure, you can look those up in your Disk application in your operating system, before you reboot your device. Just plug in your external target drive and note the full name on a piece of the paper, and do the same with the source disk or disks you want to clone.

Just to be very, very clear:

• The SOURCE disk is the one that has your data or your whole operating system (or both, in many cases)
• The TARGET disk is the empty external disk that you will want to clone to

You can see why you don't want to accidentally swap these. Once you are sure, you can proceed, and the cloning will begin. This may take some time, and progress will be shown on screen.

You can either reboot manually after it is done, or instruct Clonezilla to do that for you, but either way, you will reboot into your regular operating system, not back into Clonezilla.

Problems

As I wrote before, the interface is not very modern, and in that sense, not that user-friendly to beginners. But I have found the written instructions clear, and I appreciate that Clonezilla gives you numerous warnings and checks before it proceeds to the cloning.

I really like the disk-to-disk option, and have been grateful to have a backup of my entire operating system handy on a disk in case of emergency. I do find the fact you cannot clone identically sized disks strange. This means that I can never clone back to the original source drive from the target one. Does this mean that if I go through several rounds of cloning my system, I am going to have to keep using larger disks?

As described in my managing your disk drives post, one time, the process of cloning my laptop broke the system irretrievably. But in hindsight, that was not Clonezilla's fault. The fact that I tried to clone an already corrupted drive just revealed the problem sooner than if I would have let it play out on its own, and I was glad to be able to address it right away, though setting up your system from scratch can take weeks, especially if you use any kind of specialised software.

Ideally, you are meant to test out if your clones and images have worked, by reversing the process. With actual disk-to-disk cloning, that is quite easy to do: just open up the device, swap the drives, turn on the computer and see if it works. With images, it's a more involved process and I have to admit I have been a bit lazy testing these.

Conclusions

Cloning is a Sunday afternoon activity, because it can take a bit of time. I try to do it quarterly. It feels like you're doing good housekeeping, and sometimes it can help draw your attention to your hardware setup, a good reminder of what is going on under the hood.

In case of crashes or other emergencies, it feels really good to not only have backups of your files, but to have clone copies of the whole system as well.

Documentation

Clonezilla download page (go for the 'stable' version).

Balena Etcher, one example of image flashing software, for creating the Clonezilla USB drive.

tom'sHARDWARE, example of detailed instructions for Clonezilla. (This one does use 'expert' mode).

Similar set of instructions on linuxbabe.com.

And of course, you can search for tutorials on Youtube or Odysee, like this one by Chris Titus Tech.

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