Arch Linux

Raadush

Member

Registered: 2015-03-05

Posts: 96

[SOLVED] Timehift error: Selected snapshot device is not a system disk

Hi, I am Arch newbie, managed to successfully install the system and I wanted to make backup of my clean system if I mess something up. I installed timeshift, but when I select my btrfs partition I want to backup, I get error: Selected snapshot device is not a system disk. Select BTRFS system disk with root subvolume (@). Any help please? I tried some solutions I found on web but nothing worked. I will post any system info you may need, just say what output you need. Thanks

Last edited by Raadush (2021-06-09 09:54:44)

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

I get error: Selected snapshot device is not a system disk. Select BTRFS system disk with root subvolume (@).

can you show the output of "btrfs su li /" (as root)?

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

[root@archlinux timeshift]# btrfs su li /
ID 258 gen 11 top level 5 path var/lib/portables
ID 259 gen 12 top level 5 path var/lib/machines

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

huh, there should be more subvolumes than that, here's mine

ID 256 gen 250 top level 5 path @
ID 258 gen 254 top level 5 path @home
ID 259 gen 247 top level 5 path @var
ID 260 gen 20 top level 259 path @var/lib/portables
ID 261 gen 21 top level 259 path @var/lib/machines
ID 262 gen 101 top level 5 path timeshift-btrfs/snapshots/2021-06-08_17-43-06/@
ID 263 gen 236 top level 5 path timeshift-btrfs/snapshots/2021-06-08_18-40-14/@

you may have forgotten to create subvolumes for root and everything else during installation of your system, that's why timeshift cannot find any @ subvolume

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

And where did I forgotten them and how to create them? I was following https://wiki.archlinux.org/title/Instal … _the_disks and there is nothing about creating subvolumes and mounted mount /dev/root_partition /mnt which is i suppose your first line. My disk is partitioned as so:
/dev/sdb1        2048    1050623    1048576   512M EFI System
/dev/sdb2     1050624 1966780415 1965729792 937.3G Linux root (x86-64)
/dev/sdb3  1966780416 2000343006   33562591    16G Linux swap

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

you should create them right before pacstrap-ing your system, by :

1. mounting your btrfs drive to /mnt
2. btrfs su cr /mnt/@ (repeat for other subvolumes as needed like /mnt/@home)
3. unmount /mnt
4. mount root with specified options, example = "mount -o noatime,compress=zstd,space_cache=v2,subvol=@ /dev/sda2 /mnt"
5. mkdir -p /mnt/{home,boot,var} your subvolume names and the boot directory for boot mounting later
6. mount other subvolumes with the same exact options as root, example = "mount -o noatime,compress=zstd,space_cache=v2,subvol=@home /dev/sda2 /mnt/home"
7. mount other needed partition like boot partition for efi, and swapon
8. pacstrap to /mnt
9. genfstab -U /mnt >> /mnt/etc/fstab (to generate fstab)
10. arch-chroot /mnt to continue installation

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

Ok. I found some installation guide that works with BTRFS so maybe I try to follow this guide. Can you please check if it is what I want and correct? https://wiki.archlinux.org/title/User:A … ch_Install

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

And where did I forgotten them and how to create them? I was following https://wiki.archlinux.org/title/Instal … _the_disks

that's tutorial for ext4fs installation, naturally there would be no mentioning of btrfs subvolume creation

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

And where did I forgotten them and how to create them? I was following https://wiki.archlinux.org/title/Instal … _the_disks

that's tutorial for ext4fs installation, naturally there would be no mentioning of btrfs subvolume creation

Ok, what about that other guide? https://wiki.archlinux.org/title/User:A … ch_Install, is it ok? Its from 2016

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

Ok. I found some installation guide that works with BTRFS so maybe I try to follow this guide. Can you please check if it is what I want and correct? https://wiki.archlinux.org/title/User:A … ch_Install

if you're going to use timeshift, it'll gave you the same exact error, timeshift only support ubuntu-style subvolumes (which is (@) root subvolume) if you're going to follow that tutorial, that means you won't be using timeshift but you could probably use other btrfs snapshot manager like snapper

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

It does not matter what I use. Only timeshift is only one I know.

Last edited by Raadush (2021-06-08 12:21:05)

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

you should create them right before pacstrap-ing your system, by :

1. mounting your btrfs drive to /mnt
2. btrfs su cr /mnt/@ (repeat for other subvolumes as needed like /mnt/@home)
3. unmount /mnt
4. mount root with specified options, example = "mount -o noatime,compress=zstd,space_cache=v2,subvol=@ /dev/sda2 /mnt"
5. mkdir -p /mnt/{home,boot,var} your subvolume names and the boot directory for boot mounting later
6. mount other subvolumes with the same exact options as root, example = "mount -o noatime,compress=zstd,space_cache=v2,subvol=@home /dev/sda2 /mnt/home"
7. mount other needed partition like boot partition for efi, and swapon
8. pacstrap to /mnt
9. genfstab -U /mnt >> /mnt/etc/fstab (to generate fstab)
10. arch-chroot /mnt to continue installation

if you're insisting on using timeshift, this might be able to help

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Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

I will try it this evening, thanks. Will say how it went

Raadush

Member

Registered: 2015-03-05

Posts: 96

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

Looks much better now:
ID 256 gen 43 top level 5 path @
ID 257 gen 43 top level 5 path @home
ID 258 gen 43 top level 5 path @var
ID 259 gen 36 top level 5 path @opt
ID 260 gen 43 top level 5 path @tmp
ID 263 gen 17 top level 258 path @var/lib/portables
ID 264 gen 18 top level 258 path @var/lib/machines
ID 267 gen 38 top level 5 path timeshift-btrfs/snapshots/2021-06-08_16-33-29/@
ID 268 gen 38 top level 5 path timeshift-btrfs/snapshots/2021-06-08_16-33-29/@home

FYI in the end, I followed this great guide https://www.nishantnadkarni.tech/posts/ … tallation/. Timeshift is now working like a charm.

thatevan

Member

Registered: 2021-06-08

Posts: 12

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

nice, if your issue is solved, don't forget to mark resolved threads by editing your initial posts subject with [SOLVED]

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eisGeist

Member

Registered: 2023-08-18

Posts: 2

Re: [SOLVED] Timehift error: Selected snapshot device is not a system disk

Looks much better now:
FYI in the end, I followed this great guide https://www.nishantnadkarni.tech/posts/ … tallation/. Timeshift is now working like a charm.

Hi there!

Is there any different URL for this guide?
The one you posted refers to domain now available for purchase.

I am an Arch newbie coming from MacOS and I am trying to have a kinda "Time Machine" backup system.
Can you kindly point me to some readings where I can start?

Many thanks in advance!