What is fsbackup?

fsbackup is a ZFS-native rsync backup system for home labs. It runs directly on the backup server as a systemd service, pulls backups from remote hosts over SSH, and stores them as ZFS snapshots on a local drive.

How it works

fsbackup rsyncs each target into a dedicated ZFS dataset. After a successful sync, it creates a ZFS snapshot named for the type and date — for example, @daily-2026-03-23 or @weekly-2026-W12. ZFS deduplicates unchanged data at the block level across snapshots, making storage efficient without the fragility of hard-link trees.

Snapshots are organized by type:

Retention is enforced daily by fs-retention.sh, which uses zfs destroy to remove the oldest snapshots beyond the configured keep count.

Data classes

Backup targets are grouped into classes. Each class has its own schedule and set of systemd timers:

• class1 — application data, databases, personal files (default: daily + weekly + monthly)
• class2 — infrastructure config: Docker stacks, nginx, DNS zones (default: daily + weekly)
• class3 — large archives: photos, video libraries, media collections (default: monthly)

What runs on the server

fsbackup runs directly on the backup server as the fsbackup system user (UID 993). There is no Docker container. The system consists of:

• Bash scripts in /opt/fsbackup/bin/ and /opt/fsbackup/utils/
• systemd service and timer units (one per class and job type)
• A FastAPI + HTMX web UI (fsbackup-web.service)

What lives where