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hexdump0815 / imagebuilder

velvet os - simple script framework to build ubuntu 22.04 lts jammy (in older versions also 20.04 lts focal) and debian 12 bookworm (in older versions also 11 bullseye) bootable usb / sd card images for some arm and intel devices - lots of prebuilt images as well
GNU General Public License v3.0
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Suggestion: Ubuntu @/@home btrfs subvolume layout #18

Open stsichler opened 3 years ago

stsichler commented 3 years ago

Hi Hexdump, first: thank you for your work on that images!!! I'm very happy with it using your Ubuntu 20.04 image for my Odroid-U3. I have a small suggestion: Now, as you switched to btrfs as rootfs, what do you think about using the Ubuntu-typical @/@home btrfs subvolume layout to allow the usage of timeshift right out-of-the-box? This could be very handy when things are suddently messed up... As I pointed out here, due to timeshift's internals, this would also require to name the root partition explicitly by UUID in the fstab. Also a change in extlinux.conf would be necessary, namely selecting the correct boot subvolume using kernel option rootflags=subvol=@, because timeshift seems to also require that the default subvolume of rootfs stays /.

hexdump0815 commented 3 years ago

thanks for the positive feedback and thanks for that idea. i'll have a look at it (i'm not that famliar with timeshift and just have a rought idea what it does) and will see how well it would fit in and which advantages and disadvantages it might have ... what is the main usage scenario: to timeshift backup the home dir or the complete system?

stsichler commented 3 years ago

The purpose of Timeshift is to create and restore snapshots of the System without affecting user data in home directories (its's similar to what is called "system restore points" in Windows). This is done by using btrfs subvolume snapshots of the '@' subvolume, where the whole system files reside in, whereas the '@home' subvolume containing all home directories always stays untouched.

There are also hooks into package managers for automatic creation of snapshots before package install/remove actions, which is also very handy, besides of regular schedule-based snapshots and manual snapshots. See timeshift-autosnap and timeshift-autosnap-apt.

Timeshift is very similar to Snapper from OpenSUSE. Also for Snapper, there is a hook into package management for automatic snapshot creation on apt transactions, see apt-btrfs-snapper.

I'm not sure which one of them I like more.