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System

Storage and Btrfs snapshots

SkillFishOS's safety net: automatic snapshots and rollback from boot.

One of SkillFishOS’s central ideas is being able to tinker without fear. This is made possible by the Btrfs filesystem with automatic snapshots: every important change is captured, and if something breaks you go back in one click.

Separate subvolumes

The disk uses two distinct Btrfs subvolumes:

  • @rootfs — the operating system;
  • @home — the user’s data.

Keeping them separate is essential: rolling back the system does not touch personal files. You can return to a “yesterday” system while keeping today’s documents, saves and settings.

Automatic snapshots with Snapper

SkillFishOS uses Snapper with a root configuration and pre/post hooks on APT: every time you install or upgrade packages, a snapshot is created automatically before and after. So if an update causes problems, the “before” snapshot is already there.

Configuration highlights:

  • a cap on the number of retained snapshots so the disk doesn’t fill up;
  • snapshots kept at important system milestones;
  • management also via the Btrfs Assistant graphical tool.

Rollback from the boot menu

Thanks to grub-btrfs (with the grub-btrfsd daemon), snapshots appear directly in the GRUB menu, under “SkillFishOS snapshots”. In case of a problem:

  1. reboot;
  2. from the GRUB menu pick a working previous snapshot;
  3. boot into that state and, if you want to make the return permanent, complete the rollback.

This is the “safety net” that lets even the youngest users explore the system without fear of breaking it irreversibly.

Why Btrfs and not Timeshift

SkillFishOS chose Btrfs + Snapper + grub-btrfs over solutions like Timeshift because:

  • the APT integration is automatic (a snapshot on every package operation);
  • the snapshots are native to the filesystem (instant, copy-on-write, cheap);
  • rollback is available from boot, even if the system no longer starts normally.

Sources