Shrinking a Btrfs partition from Calamares


I would like to know why in the installation of Manjaro (currently Sikaris 22.0.4), from Calamares, having a Btrfs partition that occupies the entire disk, why when I select the Shrinking option to divide the partition in two and create a new one to install a new Linux, the new partition that it creates is always of type Ext4, it does not give me the option to choose the type of the new partition, nor that the new partition is of the same type as the other, Btrfs, seeing me forced to have a partition with a Linux in Btrfs and another partition with another Linux on Ext4, when what I want is to have two partitions of type Btrfs with a Linux installed in each of them.

From my point of view the most logical thing would be for the new partition, by default, to be the same type as the one I’m shrinking and splitting, although it could later be changed on install (in the same way as when you choose to install on the entire disk, it gives you the option to choose the type of partition).

I would like to know if there is some technical reason for this behavior, or some reason why you can’t have two Btrfs partitions with two different Linux on the same disk.


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This is something I’ve been wondering about as well. I vaguely remember that you can alter the default file system in Calamares’ partition.conf, but never tried it myself.

You can file a feature request to and they might follow your line of thought. But their reasoning is that ext4 is default and for other filesystem options use manual partitioning.

But I can’t use the manual partition system if the partition already exists, since I’m forced to do a shrink in order to keep the original partition data. If I’m not mistaken, the manual partition would only allow me to delete the original partition, which occupies the entire disk, and create two, but as I said, the content of the original partition would be lost.

You can use the partitioner program that comes bundled with the live environment (e.g. KDE Partition Manager) to make whatever changes you want before running Calamares.

Response from

‘Currently Calamares allows choosing the filesystem when using both the “Erase Disk” option and the “Replace Partition” option. The only time we don’t offer the choice is when using the “Install Alongside” option which does seem like a feature gap.’

And the request has been marked as feature: improvement, so let’s hope to see it soon implemented in a future version of Calamares.


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