Arch Linux

9bit

Guest

BTRFS Layout confusion

Hi,

I'm trying to find a reliable and commonly used btrfs layout. I'm both new to Arch and btrfs.

Here's what confuses me:

1)
The wiki has a section https://wiki.archlinux.org/title/Snappe … tem_layout. The very first paragraph reads:

> Note: The following layout is intended not to be used with snapper rollback, but is intended to alleviate the inherent problems of #Restoring / to its previous snapshot. See this this forum thread.

Isn't the primary purpose of having a multi-subvolume layout to work with snapshots without the risk of data loss on rollback? Snapper is one of two major tools to work with snapshots, as far as I understand. So when looking up a recommended layout, I was surprised that I should not use it with snapper.

In addition to that, the link that "#Restoring / to its previous snapshot" points to, does not mention any problems to be aware of. So I really don't understand what the author of that part is trying to tell me. And ultimately, I'm left confused and really don't know what to do now. I also think that the article is in need of some clarification, especially an explanation on the reason for some of the warnings.

2)
I looked for other places that discuss btrfs layouts. I found this GitHub issue: https://github.com/archlinux/archinstall/issues/781

Multiple recommendations are discussed, all of which include having a subvolume for /root at /@/root. My understanding is that the conclusion was to implement the following layout in the archinstall:

[root@bigrigv2 archinstall]# findmnt --real
TARGET                                    SOURCE                     FSTYPE      OPTIONS
└─/mnt/archinstall                        /dev/loop0p2[/@]           btrfs       rw,relatime,ssd,space_cache=v2,subvolid=256,subvol=/@
  ├─/mnt/archinstall/boot                 /dev/loop0p1               vfat        rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro
  ├─/mnt/archinstall/.snapshots           /dev/loop0p2[/@.snapshots] btrfs       rw,relatime,ssd,space_cache=v2,subvolid=257,subvol=/@.snapshots
  ├─/mnt/archinstall/home                 /dev/loop0p2[/@home]       btrfs       rw,relatime,ssd,space_cache=v2,subvolid=258,subvol=/@home
  ├─/mnt/archinstall/var/cache/pacman/pkg /dev/loop0p2[/@pkg]        btrfs       rw,relatime,ssd,space_cache=v2,subvolid=260,subvol=/@pkg
  └─/mnt/archinstall/var/log              /dev/loop0p2[/@log]        btrfs       rw,relatime,ssd,space_cache=v2,subvolid=259,subvol=/@log

Here, /@/root was dropped and I didn't find an explanation in the issue on why.

I hope for some clarificaton on these points, and maybe a recommendation on where to go from here. My gut feeling tells me to use the recommendation from 2) and add a subvolume for root just like home. But I'm also new to any of this and lack the experience to make a good call.