Defragger
Defragger is a graphical Linux filesystem defragmenter that maps file, free-space, and metadata allocation and analyzes fragmentation.
What Defragger is
Defragger is a graphical Linux filesystem defragmenter that maps file, free-space, and metadata allocation and analyzes fragmentation. Its adaptive block map gives a visual view of filesystem layout. It can defragment ext4 while online, and defragment and compact FAT16 and FAT32 when offline. FAT12 and exFAT are supported 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; operations that require them go through a PolicyKit-authorized helper over D-Bus. Defragger is free and open source, dual-licensed under MIT or Apache License 2.0. The project describes it as alpha and advises backing up important data; ext4 has received the most testing, while FAT write support is newer. It requires Linux with Qt 6 and KDE Kirigami. Privileged mode also needs systemd and an active graphical PolicyKit agent.
Good
- Visualizes file, free-space, and metadata allocation
- Supports online ext4 defragmentation
- FAT16 and FAT32 can be compacted offline
- Includes command-line volume operations
- Free and dual-licensed open source
Watch out
- Described as alpha software
- FAT12 and exFAT are analysis-only
- FAT write support is newer
- Requires Qt 6 and KDE Kirigami
Who it suits
Defragger suits Linux users who want a graphical or command-line way to inspect fragmentation and work with supported filesystems. It is most appropriate for users prepared to heed the backup advice, especially when writing to FAT volumes.
Verdict
Defragger offers both visual and command-line filesystem tools, with online ext4 support and offline FAT16/FAT32 operations. Its alpha status and newer FAT write support make the stated backup precautions important.
Plans and prices
From Defragger's own pricing page, checked 4 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Open-source | Free | Alpha software · Linux only · ext4 and offline FAT16/FAT32 write support |
The facts
Each one read from Defragger's own pages, with the date it was checked.
What it does
- Analysis
- It analyzes fragmentation and displays an adaptive filesystem block map.checked 4 Oct 2026
- CLI
- The project includes a command-line interface for listing, analyzing, defragmenting, and compacting volumes.checked 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.checked 4 Oct 2026
- FAT caution
- FAT write support is newer and the README recommends first using it with disposable or fully backed-up volumes.checked 4 Oct 2026
- Filesystem support
- It supports online ext4 defragmentation and offline FAT16/FAT32 defragmentation and compaction.checked 4 Oct 2026
- Integrations
- For ext4 operations, Defragger uses Linux filesystem ioctls directly and says it does not shell out to e4defrag or filefrag.checked 4 Oct 2026
- License
- Defragger is dual-licensed under MIT or Apache License 2.0.checked 4 Oct 2026
- Privilege handling
- The GUI and CLI run unprivileged, with elevated operations handled by a PolicyKit-authorized helper over D-Bus.checked 4 Oct 2026
- Purpose
- Defragger is a graphical Linux filesystem defragmenter that visualizes file, free-space, and metadata allocation.checked 4 Oct 2026
- Read-only formats
- FAT12 and exFAT support analysis only; neither is writable.checked 4 Oct 2026
- Support
- The repository exposes GitHub Issues, which showed zero open issues when viewed.checked 4 Oct 2026
Where it runs
- 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.checked 4 Oct 2026
The company
- Maker
- The README credits copyright 2026 to Guillaume Binet, and the maker's GitHub profile lists Austin, TX.checked 4 Oct 2026
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