We’ve got the green light from the corporate to upgrade MBP (Mac Book Pro) to Big Sur. There is only one TINY prerequisite: 35.5GB of available storage.
I only had less than 10 GB free space.
Why? My MBP has 250 GB SSD. The Operating system file system is partially case insensitive. This is inconvenient when working with git and code. Renaming a file case is not working as expected on such file system. In order to overcome that I created another partition that is case sensitive — Changing the OS partition to case sensitive is not recommended (here is one example).
When I got the new MBP in the past I split the SSD Drive into two partitions: the main os remain case insensitive, and all my code is on a case sensitive partition.
The OS partition now have 125GB and it was full. I tried cleaning up but did have enough free space yet.
To find why I ended up using JDiskReport. The tool has classic UI but it does the job. After scanning “/” directory and starting to I discovered one big file that takes 60 GB:
After checking that dir I found that docker on mac is keeping all its images in one file and was preserving for that 60GB — although I actually used only 10GB for images. Changing that size on docker settings to 15GB did the trick (although it erased all existing images :( ).