Clonezilla image size smaller than expected

Question

I just used Clonezilla for the first time today. It seemed to go well, but the resulting image is smaller than I expected.

The parition that I wanted to clone has about 21GB of space used on it, yet the image is only about 12GB. Is this normal? Shouldn't the image be about the same size as the space used on the partition?

I have 3 partitions on my drive. A Windows partition, an Ubuntu partition and a storage partition.

This is the partition that I tried to clone , sda5 (Ubuntu partition).

This is the details of the image that was created by Clonezilla:

Here is some info on all my partitions:

All partitions

What's going on here? Why is my image smaller than the space consumed on the partition? I would really appreciate some help.

Thanks!

Solution

I just checked in the image folder, the largest files in there have the extensions "gz.aa", "gz.ab" and "gz.ac", which I think is a compressed format, right? The partition I cloned had very few media files in it. It contained mostly system files and installed software. since it was my Ubuntu partition. So I guess this seems that compression was indeed used and that the smaller size of the image is perfectly in order.

Correct, Clonezilla used gzip compression and file splitting when storing the image.

You can check this with the file command. That should tell you if it really is a gzip compressed file or something else.

Reducing the file size by half is a typical result when using gzip. Some other compression tools are more efficient but slower (xz, lzma) or a bit less efficient but much faster than gzip (lzop, lz4). And there is also zstd.

Knowing the compression used on the files, you could decompress the image and loop mount with mount to check if the filesystem is still consistent. The following command can be used to decompress the image:

cat your_image_name.gz.* | gzip -d > uncompressed_image.img

Use the equivalent program to gzip and refer to the corresponding man page if file returned something else than gzip.

Comments

[Arronical]

Did you do a device-image clone or a device-device clone? I'm thinking maybe Clonezilla has some way of compressing the used space further when creating the image file.

[Fiksdal]

That would make sense if Clonezilla includes compression. I don't understand what you mean by device-image, etc. I'm not very experienced with these things. I saved the image on an external drive, and selected encryption mode in Clonezilla. I basically followed this guide clonezilla.org/show-live-doc-content.php?topic=clonezilla-li‌​ve/…

[TrailRider]

if using device-to-image Clonezilla will, by default compress the image. If using the "beginner" settings compression is part of the default settings. If this was the setting used I would suspect that the size is correct but I have no way to know that for sure, the total compression would depend on how many of your files were already compressed(Mp3's for ex.). You could check the clonezilla-img file in the clone folder. one of the other default settings is that that image is checked as "restorable" the last 15 lines (or so) will give the results. If it's restorable, it should be fine

[Fiksdal]

Thanks, TrailRider, that makes a lot of sense! I did use beginner settings. I just checked in the image folder, the largest files in there have the extensions "gz.aa", "gz.ab" and "gz.ac", which I think is a compressed format, right? The partition I cloned had very few media files in it. It contained mostly system files and installed software. since it was my Ubuntu partition. So I guess this seems that compression was indeed used and that the smaller size of the image is perfectly in order. Thanks so much for your comments.

[Fiksdal]

Alright, thanks for the confirmation. Thanks also for the instructions on how to make absolutely sure. Although a bit too technical for me to fancy trying that right now. Anyway, I think the image is probably fine. Clonezilla ran perfectly, and since the file size is also normal, that's all I need! Thanks! :)

[Csabi Vidó]

@Fiksdal Note that you get a few more points reputation when you accept an answer. ;)