Ubuntu – Clonezilla image size smaller than expected


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.


Best Answer

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.

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