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Defragger
What it is
Defragger is a free, open-source graphical tool for analyzing and defragmenting Linux filesystems. Its adaptive block map shows how files, free space, and metadata are allocated, and the software analyzes fragmentation. It can defragment ext4 while the filesystem is online; FAT16 and FAT32 can be defragmented and compacted offline. FAT12 and exFAT are available for analysis only and cannot be written. A command-line interface can list, analyze, defragment, and compact volumes. The GUI and CLI run without elevated privileges, while operations that need elevation use a PolicyKit-authorized helper over D-Bus. For ext4 work, Defragger uses Linux filesystem ioctls directly rather than calling e4defrag or filefrag. It requires Linux with Qt 6 and KDE Kirigami; privileged mode also requires systemd, PolicyKit, and an active graphical PolicyKit agent. The project describes the software as alpha, recommends backing up important data, and notes that ext4 has received the most testing. FAT write support is newer, so the project recommends starting with disposable or fully backed-up volumes. It is dual-licensed under MIT or Apache License 2.0.
For and against
For
- Free and open source under two licenses.
- Graphical block map and command-line interface.
- Supports online ext4 defragmentation.
- Can compact offline FAT16 and FAT32 volumes.
Against
- The project describes the software as alpha.
- FAT12 and exFAT are analysis-only.
- FAT write support is newer and warrants caution.
- Requires Linux, Qt 6, and KDE Kirigami.
The verdict
Defragger provides visual analysis and operations for ext4 and selected FAT filesystems, with both graphical and command-line interfaces. Its alpha status and cautions around backups, especially for FAT writes, are important considerations.
Who it suits
Defragger suits Linux users who want to inspect filesystem allocation or work with supported ext4 and FAT volumes. It may be useful to users comfortable with alpha software and the project's backup cautions.
Plans and prices
Open-source
Alpha software · Linux only · ext4 and offline FAT16/FAT32 write support
Read 4 Oct 2026 · github.com
On the record
- Analysis
- It analyzes fragmentation and displays an adaptive filesystem block map.github.com · read 4 Oct 2026
- CLI
- The project includes a command-line interface for listing, analyzing, defragmenting, and compacting volumes.github.com · read 4 Oct 2026
- Data safety
- The README warns that the software is alpha, recommends backing up important data, and says ext4 has received the most testing.github.com · read 4 Oct 2026
- FAT caution
- FAT write support is newer and the README recommends first using it with disposable or fully backed-up volumes.github.com · read 4 Oct 2026
- Filesystem support
- It supports online ext4 defragmentation and offline FAT16/FAT32 defragmentation and compaction.github.com · read 4 Oct 2026
- Integrations
- For ext4 operations, Defragger uses Linux filesystem ioctls directly and says it does not shell out to e4defrag or filefrag.github.com · read 4 Oct 2026
- License
- Defragger is dual-licensed under MIT or Apache License 2.0.github.com · read 4 Oct 2026
- Linux requirements
- The stated environment is Linux with Qt 6 and KDE Kirigami, while privileged mode requires systemd, PolicyKit, and an active graphical PolicyKit agent.github.com · read 4 Oct 2026
- Maker
- The README credits copyright 2026 to Guillaume Binet, and the maker's GitHub profile lists Austin, TX.github.com · read 4 Oct 2026
- Privilege handling
- The GUI and CLI run unprivileged, with elevated operations handled by a PolicyKit-authorized helper over D-Bus.github.com · read 4 Oct 2026
- Purpose
- Defragger is a graphical Linux filesystem defragmenter that visualizes file, free-space, and metadata allocation.github.com · read 4 Oct 2026
- Read-only formats
- FAT12 and exFAT support analysis only; neither is writable.github.com · read 4 Oct 2026
- Support
- The repository exposes GitHub Issues, which showed zero open issues when viewed.github.com · read 4 Oct 2026
