Understanding btrfs Assistent and Snapper

Framework Laptop 13 Linux
1

Hi,
I set up Btrfs Assistent to use Snapper.

afbeelding
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As you can see, that seems to work.
What I don’t understand, is where exactly Snapper is used for. Does it do an incremental sync of my complete root folder? If I choose “Browse”, I can see my folder structure, but as you can see, a lot of the directories are empty:
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Is that because the sync isn’t ready yet? Could I retrieve a single file this way, or isn’t that the purpose of Snapper?
Thanks for pointing me in the right direction!

2

Snapper creates btrfs snapshots at the interval you set in btrfs assistant. Snapshots are not backups and also not synced in any way. Image it to be an image at that point in time of your files. It uses a system called Copy-on-Write. But I’m not going to explain all that. It does some magic under the hood such that snapshots only store the differences between the time the snapshot was taken vs the current state. Don’t think about it, it works :wink:

It is normal for those directories to be empty. .snapshots stores the snapshots, so it isn’t included in the snapshot itself.
afs, mnt, media and dev are always empty in snapshots as these usually only contain mount points (and you can’t save a mount point)
boot is on a different partition, so it isn’t included.
home is a different subvolume, so also not included.

If you want to create snapshots of your home directory, you will have to configure that in btrfs assistant.

Don’t create too much snapshots, it slows down you system at some point.

But yes you can retrieve a single file using this! In the browse window of btrfs assistant, select the file you want to restore and press restore! Or there are different more difficult ways you can Google :slight_smile:

1 Like
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Thank you!
I indeed don’t completely understand it, but I’ll trust the magic :slight_smile: .
Now and then, I reed some background-information about my system and Linux and all that. So one day I will understand more!

Only one thing: with how it is set-up now, can I restore my system in case of a crash?

4

Depends on the crash.

  • issue with the disk? No as this is not a backup

  • Corrupted files? Maybe

  • Catastrophic system update failure? Yes!

  • bootloader issue? No

  • messed up configuration files? Yes

  • Accidentally deleted some important document? No, as you don’t have snapshot set up for your home subvolume.

You can think of a subvolume as a partition (it isn’t, it’s more like a fancy directory, but different :wink: )
The btrfs docs could be an interesting read if you have time for it :slight_smile:

1 Like
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Thanks. I did read some of it, but it’s hard to grasp from a first time reading.
There’s not much in my home-folder, I have a NextCloud-folder where most of my important files are (so that’s save in my NextCloud-space, which is hosted and the hosting company also keeps backups, so that’s 3 versions).
AND I have Vorta, which has a backup of almost evetything, just not of etc/, because there’s permission-problems with that…