Fedora 32 Looking At Turning Up SquashFS Compression For Smaller Install Media

While Fedora 32 is already making it so CD / DVD install issues shouldn't block releases given most users are doing USB-based installations for the past number of years, Fedora is still trying to decrease the amount of space the install media takes up regardless of CD/DVD/USB media.

A late change proposal for Fedora 32 is improving the compression ration of the SquashFS file-system on the installation media. The proposal by Red Hat's Bohdan Khomutskyi is to tune the SquashFS compression settings to yield a better compression ratio and/or reduction of CPU usage at build time.

Here are some of the metrics acquired by Bohdan during testing:

With some tuning it was possible to make the SquashFS and EXT4 image ~6% smaller while also consuming about 35% less CPU time. If resorting to plain SquashFS without nested EXT4, the install media could be about 10% smaller and still have around 30% less CPU time.

The exact SquashFS tuning is still to be determined, pending approval by the Fedora Engineering and Steering Committee for this late change.

More details on the Fedora mailing list.