I recently ran into a problem where my computer can no longer wake properly from sleep, forcing me to shut it down every night. It made me realize I should have system snapshots available in case an update or configuration change breaks something. I already back up my personal files to a separate external drive, so I mainly want Timeshift for restoring system files and settings.
My understanding was that Timeshift backs up everything by default, but I've since read that it normally excludes /home. Should I include the system directories while excluding /home, or is that already the default configuration? If an update causes a problem, can I restore a Timeshift snapshot while leaving my personal files untouched?
Also, what is the recovery process if the system becomes unbootable or I can't log in? My external drive is formatted for use with Windows and contains other backups, so I'd prefer not to reformat it unless necessary. Are there alternatives that can store a system backup on that kind of drive?
4 Answers
If your system uses Btrfs, Timeshift can use filesystem snapshots. They are very fast and space-efficient because unchanged files are shared rather than copied. They’re useful for undoing updates or configuration mistakes, but they are not a complete backup: disk failure or filesystem corruption can affect both the original data and the snapshot. Traditional snapshot mode on other filesystems is slower and uses more storage.
You do not necessarily need to dedicate the entire external disk to Timeshift, but the filesystem and mount permissions have to be suitable for the backup method you choose. If the drive is formatted for Windows, a Linux backup tool that supports that filesystem may be more practical, or you can create a separate Linux-compatible partition. Keep your personal-file backups separate from system snapshots, since restoring a system snapshot is not a replacement for a real data backup.
That is essentially Timeshift’s normal behavior. It is intended to protect system files and settings while excluding /home, so restoring a snapshot can undo a troublesome update without replacing your personal files. Check the snapshot settings before relying on it, since the include and exclude lists can be changed manually.
That clears up my confusion. I may have changed the defaults when I first set it up and then forgotten about it, so I’ll verify the exclusions before creating new snapshots.
If the installed system will not boot, start a live Linux USB and install or run Timeshift from there. Mount the system and snapshot drive, select the snapshot, and restore it from the live environment. It’s worth testing that the snapshot disk is accessible before you need it, and keeping a live USB available. Timeshift is mainly for system recovery, not protection against a failed or corrupted drive.
I was using snapshots and backups as if they meant the same thing. My main goal is to undo a bad update, while my personal files are already backed up separately, so snapshots sound appropriate for that use.