In the upcoming Fedora 42 release, scheduled for late April, there are plans to transition all Live builds of the distribution from SquashFS to the EROFS file system, support for which was implemented last year in the Dracut 103 toolset for creating bootable images. This proposal has yet to be approved by the Fedora Engineering Steering Committee (FESCo), which oversees the technical aspects of Fedora's development.
The reasons for this transition include the more active development of EROFS (the last release of the SquashFS toolset was in spring 2023) and the advanced capabilities in EROFS that may be leveraged in the future. All builds that utilize a read-only system image, such as Live builds with KDE, Xfce, Budgie, LXQt, MiracleWM, and COSMIC, as well as the Fedora KDE Plasma Mobile and Fedora CoreOS Live editions, are intended to switch to EROFS.
The SquashFS and EROFS file systems are designed for read-only operation and provide a compact representation of metadata and storage of data in a compressed format. EROFS (Extendable Read-Only File System) was created by Huawei and focuses on achieving maximum performance. EROFS employs a method of data compression that differs from other file systems, using resulting compressed blocks of fixed size (in other file systems, blocks are fixed before compression, resulting in varying sizes after compression).
Compared to SquashFS, EROFS has a lower compression level (image size of 2.7 GiB in EROFS versus 2.0 GiB in SquashFS using the XZ compression algorithm, and 3.9 GiB versus 3.1 GiB using LZ4), but offers higher random access speed and bandwidth (7.1 MiB/s in EROFS compared to 5.0 MiB/s in SquashFS for XZ and 30.9 MiB/s compared to 26.3 MiB/s for LZ4). When compared to Ext4, EROFS significantly outperforms in random data access — at a compression level of 4, EROFS was nearly 3 times faster on Flash storage and 6 times faster on a hard disk.
Source: opennet.ru
