Add a snapshot manager, and start covering home

The machine already had snapper running hourly on btrfs, so the tool was never missing. What was missing is that snapper's only configuration covered / -- and /home is a separate subvolume with no configuration at all. Six hundred and forty-three snapshots existed and not one of them contained a document. Anyone reaching for file history would have found their system and none of their files. /home now has a configuration on the same hourly timeline, with deliberately conservative retention: Steam's 1.2 TB lives on that subvolume and churns on every game update, so keeping five hourly and seven daily bounds what those updates can pin. Per volume, because on this machine "one is covered and the important one is not" was the news, and a timeline opening on system snapshots would have buried it. Inside a volume the timeline is the familiar view: points in time, newest first, each openable as a folder tree to take a file out of. Restoring sets the current version aside as .before-restore-N rather than overwriting it. A restore that destroys the thing you were about to compare against is how someone loses the work they were trying to save. Rollback is deliberately absent. snapper's rollback changes the btrfs default subvolume, and this system's fstab pins subvol= explicitly, which overrides it -- so a rollback would report success and change nothing after a reboot. A recovery feature that silently does nothing is worse than not having one, and making it work means editing fstab and the bootloader, whose failure cannot be repaired from inside the desktop. Per-snapshot size is reported as not measured, because measuring it needs btrfs quotas that cost performance on every write. Free space is shown instead, which is the number that decides anything. Claude-Session: https://claude.ai/code/session_01BRvzt4H8XXLPVH5MyYdk9L
2026-08-19 16:11:50 -04:00
parent e9d567aa72
commit 1f40f8e136
11 changed files with 1093 additions and 1 deletions
@@ -178,6 +178,30 @@ modifies or deletes existing data; restore copies out rather than over.
 **Done when** losing the home directory is an inconvenience rather than a
 catastrophe.

+**Landed 2026-08-19, as snapshots rather than backups.** The machine already had
+snapper running hourly and btrfs underneath, so the tool was never the gap. The
+gap was that snapper's only config covered `/`, and `/home` is a separate
+subvolume with no config at all -- six hundred and forty-three snapshots existed
+and not one of them held a document. A `home` config now exists, the hourly
+timeline covers it, and retention is deliberately conservative (5 hourly, 7
+daily, 4 weekly) because Steam's 1.2 TB lives on that subvolume and churns on
+every game update.
+
+Restore is file and folder level, and sets the current version aside as
+`.before-restore-N` rather than overwriting it.
+
+**Rollback is deliberately absent, and this is the interesting part.** snapper's
+rollback works by changing the btrfs default subvolume. This system's fstab pins
+`subvol=root` and `subvol=home` explicitly, which overrides the default -- so a
+rollback would report success and change nothing after a reboot. A recovery
+feature that silently does nothing is worse than not having one. Making it work
+means editing fstab and the bootloader, which is the one class of change whose
+failure cannot be fixed from inside the desktop; it deserves its own tested plan.
+
+**Still open.** Whether to carve Steam onto its own subvolume so snapshots skip
+it. Deferred on purpose: the page reports free space, so the cost can be watched
+for a week and decided on evidence.
+
 ---

 ## Order and reasoning