Timeshift partial restore

Question

Timeshift can be configured to include Home in snapshots. That could potentially be harmful without the ability to do a partial restore. In the event you need to restore the OS from a weeks or months old snapshot, that would also restore obsolete versions of your documents.

Including Home in the snapshot seems practical only if you can specify to not include Home in the restoration when that is undesirable. I haven't been able to find explicit documentation on doing that.

The only apparent selection option for Timeshift restore is whether to restore to each original partition. The guidance doesn't explain what happens if you deselect a restoration destination. Timeshift can restore to partitions other than the original source. So deselecting a default destination like Home could mean a number of things:

• Timeshift filters the restoration to exclude files from the deselected destination.
• Timeshift goes through the motions of restoring those files to nowhere, producing harmless error conditions.
• Timeshift restores those files into the root partition rather than what may have been a separate Home partition since Home is a root subdirectory (i.e., this option is more of a "where" selection than an "if" selection).

Question: If Home is included in Timeshift snapshots, what is the procedure to restore root without restoring Home?

Answer 1

The feature to deselect destinations for restoration is not covered in the user documentation; not use-cases or the specifics of what happens if a destination is deselected. But the developers' documentation (readme.md) seems to make clear that the purpose of this feature is not to enable inclusion of Home in the snapshot and then exclusion of it from a restore.

The section User Data is Excluded by Default explains that Timeshift is designed to protect system files and settings and is not meant to protect user data, specifically for the reason stated in the question. Timeshift is designed to perform full restoration of a snapshot, which would overwrite user data if that was included.

So while it might be possible to exclude Home from a restoration if that's how the destination deselection feature works, it is not a supported mode of operation or consistent with the intent of the application.

Bottom line: nothing prevents someone from experimenting on their own with the features. However, there are other applications designed to backup user data. Even if Timeshift could be used this way, it wouldn't be the best tool for the job. It would also introduce some risk by relying on an additional, non-standard procedure to prevent overwriting user data.

Alternate use: If someone wanted to use Timeshift to store snapshots of their user files, and was happy with the design features of the application for this purpose, the configuration provides for selecting root and/or user files and the storage location for the snapshots. The issue of overwriting user files in a system restore could be avoided by creating a completely separate set of snapshots for user files (one set root-only, the other set user-only).

However, Timeshift is designed as a single-user application. It can't differentiate multiple users or store to multiple locations. So implementing this would require unsupported customization, perhaps creating a wrapper for Timeshift. Again, this comes back to the fact that there are better-suited, off-the-shelf solutions.

Answer 2

Timeshift is not a substitute for proper backup procedures. If you need to reinstall '/', then a system reinstall is generally quicker - this is much simpler if your /home directory is on a separate partition or disk. Of course your main offline backup procedure needs to include details of any system customisations etc.

It can be useful to use Timeshift to restore a few system files e.g. to recover a few config files that you accidentally corrupted. Additionally, because Timeshift works best when it autoruns, saving to its own disk partition, this is not ideal for hardware failures.

I wouldn't recommend using Timeshift on /home - although it may be useful to include the hidden files/directories since these sometimes contain config information. Very important to exclude any cache directories, though.