Btrfs as root. See Btrfs Wiki: Conversion_from_Ext3.

Btrfs as root For user space utilities, install the btrfs-progspackage that is required for basic operations. I'm using the latest fedora, 22, which means: grub2 2. There were solutions for these, but my personal preference and hardware needed newer kernel releases. Versions must be adjusted ideally and you probably don't need to lower memory clocks I have a setup on my laptop in which there are three partitions relevant to Ubuntu: a ext4 /boot partition, a btrfs root partition on LUKS and a swap partition on LUKS. Create partitions. Use btrfs send|recv to move the temp install. As such, the above answer by Mskje can be changed to the following: Boot as normal to the live session. 02GiB devid 1 size 20. Sedm let zkušeností. What can I do to make btrfs check run properly? I'm currently learning to actively monitor/care for my linux system. Only in the @home subvolume is there a nesting for the associated snapshots. it has been running well. I have a btrfs filesystem that looks like this: root_subvol # subvolid=5 - the root subvolume for the btrfs filesystem - snapshots/ # Folder that contains btrfs snapshots of the subvol_root that I take before I do system updates - subvol_root/ # A btrfs subvolume. ) The problem with this line is that it recognizes the btrfs device after boot (as intended) but of course it can't find /lib/systemd/systemd because it's searching from the top level and not the subvolume. I normally boot my desktop from an ext4 ubuntu root filesystem, and would like to setup the same root filesystem copied into a btrfs subvolume. Maybe the menuentry doesn't need to refer to the links Making sure to change /etc/fstab from ext4 to btrfs. $ sudo btrfs subvolume list / ID 257 gen 5367 top level 5 path @ ID 258 gen 5366 top level 5 path @home ID 269 gen 5354 top level 257 path snapshots/root. Hello everyone, I recently did a clean install of OpenSUSE 13. Get the Btrfs volume label. Even on ubuntu or windows, free space shown at 40GB. 20160919-0954 To make a subvolume the new root (after Posted by u/Yiannis97s - 7 votes and 48 comments I'm using BTRFS with satisfaction (I mentioned it in 2014 and, more recently, in the IT-Notes blog). com says "With Btrfs the default on openSUSE, when will other distros follow suit," but says that while a default install uses Btrfs on root, that " a separate partition for /home, uses XFS. This mount option overrides the default subvolume set for the given filesystem. That's the normal state of affairs after creating a new partition and mounting it as root. The next step will to reboot your system. No performance issues with both running. Consulte os artigos Systemd-nspawn#Use Btrfs subvolume as container root e Systemd-nspawn#Use temporary Btrfs snapshot of container. The solution you'd like. Sometimes, after an unclean shutdown, Ubuntu would refuse to boot, and would just stop after it successfully maps the LUKS partitions and appears to mount the root partition. Since I Aside from /boot, all my partitions (including root, /) are BTRFS subvolumes. Timeshift issue #157, "Support for @rootfs subvolume" and duplicate issue, Timeshift issue #83, "Support Debian filesystem" These names are just two conventions with no technical advantages in the eyes of btrfs, but currently arbitrarily hard-coded in Timeshift as the root volume. This filesystem has one subvolume named ‘default’ (created by mkfs), and one snapshot of ‘default’ named ‘snap’ I settled for btrfs root at a time where I grew weary of digging out of upgrade troubles with kernel upgrades and a zfs root. 26GiB path /dev/sdd root@omvt:~# oot@omvt:~# I use btrfs for my rootfs. open and mount your old OS with subvolid=5. In the above, nvme0n1p7 is my btrfs partition with the two subvolumes on it, and in efibootmgr the entry I'm having problems with is "Arch Linux BTRFS". It is also called “flat layout”. I don't consider it optimal for all types of loads, but it solves many problems in many situations. Mount the new btrfs partition to /mnt: mount /dev/mapper/vg-root /mnt And mount the uefi partition to /mnt/boot: mkdir /mnt/boot mount <device 1> /mnt/boot Then run. nix from the installer. The Btrfs file system is supported in Oracle Linux, but only on UEK. This includes reading the logs after a crash and monitoring filesystem status. nix file, but the one generated by the installer is better, so let's use that one. Source: https://gist. The grandchildren remain untouched. To create GRUB BIOS, issue the following command: Migration of the existing root filesystem to Btrfs. From root this means, btrfs send piped to, as a user ssh into the backupmachine and use sudo to run btrfs receive to receive the snapshot. loader. Easiest would be making a boot partition and only root in BTRFS the other option would be compiling your own U-Boot with BTRFS support (it's not too hard to be fair after you got a bit into it) here is my PKGBUILD from back then, even with btrfs comments left. key. 2 is that the root partition cannot be encrypted, with Btrfs selected Lastly, create the actual btrfs root partition: mkfs. I simply specified btrfs during the installation process. If you need to boot from a Btrfs file system (i. In particular, it sets up any boot. This guy on LinuxBSDos. Commented Mar 15, 2023 at 22:16. ; linux-firmware: Drivers for common hardware. Devido à natureza copy-on-write do Btrfs, simplesmente acessar arquivos pode acionar a cópia e gravação de metadados. The ref-counts for the immediate children are incremented. For this guide I'll simply use /dev/sda, but it can change depending [root@server mnt]# ls -la total 24 drwxr-xr-x 3 root root 4096 May 12 11:57 . In this guide I will walk you through the installation procedure to get a Pop!_OS 22. The idea is to have a read only btrfs partition containing the basic root, and a read write partition for the changes. inf, and choose Install. You can use btrfs subvolume list of btrfs subvolume show to see subvolume ID numbers. This can be used to load any number of custom scripts, binaries, configs, etc when boot from zram. Make fedora template with btrfs root filesystem. Btrfs was created to address the lack of pooling, snapshots, checksums, and integrated multi-device spanning in Linux file systems, particularly as the need for such features emerged when Btrfs/System Root Guide — one example for re-basing a Gentoo installation's root filesystem to use btrfs; Btrfs/Native System Root Guide — alternative guide on using a subvolume in a Btrfs filesystem as the system's root; Add btrfs root parition entry to Grub2 [closed] Ask Question Asked 13 years, 4 months ago. drwxr-xr-x 18 root root 4096 May 15 00:45 . Using Btrfs as RAID on your root filesystem is also not the greatest if uptime is the goal, as you need to deal with a number of downsides both in btrfs itself and systemd (ie you need to provide the degraded mount option, which really complicates the boot process, and systemd can be problematic in that case if it's not also added to the fstab menuentry "btrfs test" { set root=(hd0,gpt4) linux /@/vmlinuz root=/dev/sda4 rootflags=subvol=@ rw quiet splash initrd /@/initrd. Installing a System With a Btrfs root File System; 7 Installing a System With a Btrfs root File System Oracle Linux uses XFS as the default file system, but it also supports other file systems such as ext2, ext4, and so on. The LUKS-encrypted btrfs root partition; So, first we need to generate the partition tables. Is there any particular reason for that? I have installed it with changed option d-i partman/default_filesystem string to btrfs as root and it works so far. Installing Packages with pacstrap; Use the pacstrap script to install essential packages in the specified root directory /mnt:. Fedora Workstation installs with btrfs by default, based on our approach to distribution defaults, we should adjust template build to use btrfs too. There are several instruction on the internet how an existing installation can be converted but they are complicated and error-prone. Reduzindo atualizações de metadados de tempo de acesso. Any thouths? cool，How Hi, I can’t finish instalation on one of my computers when using BTRFS as root filesystem. Shows a bunch of orphaned inodes which I also cannot find on the hard drive. When the system Btrfs in RAID1 as a root filesystem on Gentoo. 04 on a BTRFS root partition but i cannot get past the installer not allowing me to set the root filesystem on a btrfs partition. Reduzir a frequência das One of the best filesystems for Linux is btrfs. The user in question would need sudo access to btrfs, and I use key-based ssh access so that you don't need mount: mounting /dev on /root/dev failed: No such file or directory mount: mounting /sys on /root/sys failed: No such file or directory mount: mounting /proc on /root/proc failed: No such file or directory Target filesystem doesn't have requested /sbin/init. i have fedora 40 and work with btrfs I try to create subvolume of root @ and subvolume home with @ homo but i fall with that because if you have install the system It's difficult to change this option. Strange is that at another, installed to fresh, clean, newly partitioned SSD it works well even with BTRFS Any idea? Shini As dual boot user, i used single partition with subvol @root @home @data (for windows). Place actual installation in root subvolume (same as vanilla Fedora). ; linux: Kernel itself. Would you please post your /etc/fstab file in your original post? – paladin. sudo btrfs subvolume snapshot / /@rootfs Copy the root filesystem to the new btrfs RAID (or make a new install on it) Now you can install your system, or copy your existing root to the new raid btrfs. You could also do the same thing by splitting your drive in two as you mentioned. Therefore having an image t Hi everyone (sorry for bad English). These profiles include DUP, SINGLE, and MIXED, in addition to the conventional It's really not that much extra work to setup, just mount the root of the filesystem somewhere (/mnt/btrfs or something) move an existing directory out of the way, make a subvolume to It's common for Fedora this days when you format your system with btrfs to create a subvolume called root, so if you didn't find the subvol option in fstab, then omit root from subvol. In this case, after installing the next Linux OS on the same partition, as your Ubuntu Hi! I have noticed, that preseed file in installation media of omv 6. Install OpenSUSE to a spare drive, in a VM, etc. I have created one volume with one subvolume mounted at /. The structure of this directory mirrors the hierarchy of the root file system. And I use timeshift to snapshot it. Contains /etc, /home, /proc, Most software does this by changing the subvolume that gets mounted as root, so instead of @rootfs getting mounted to /, @snapshots/snapshot_2 or something similar gets mounted to /. github. GitHub Gist: instantly share code, notes, and snippets. I should start btrfs balance (without adding new drive, just running balance) to remove unused allocated memory. As a precaution I create a snapshot first: * Btrfs/System Root Guide — one example for re-basing a Gentoo installation's root filesystem to use btrfs * Btrfs/Native System Root Guide — alternative guide on using a subvolume in a Btrfs filesystem as the system's root * Ext4 — an open source disk filesystem and most recent version of the extended series of filesystems. Ignore bad tree roots, greatly improve the chance for data salvage. bin" in order to work correctly. . But I'm unable to mount the read write partition on top, or to boot form the read write portion. Btrfs root file system; Verify the Root File System. Btrfs is a computer storage format that combines a file system based on the copy-on-write (COW) principle with a logical volume manager (not to be confused with LVM), developed together. In my opinion, the non-nested (or flat) layout is easier to manage Přitom původně vývoj Btrfs začal kvůli získání alternativy k licenčně problematickému ZFS. Viewed 2k times 2 . , your kernel and initramfs reside on a Btrfs partition), check if your boot loadersupports Btrfs. , to use the new UUID/labels. So far I'm able to boot from the read only seed partition. A new root Q is created, initially pointing to the same nodes as the original root P . Boot the 2nd Linux system. Add a new line for the btrfs root, like the following: # The root was converted to btrfs. Thus, to install Oracle Linux with Btrfs, you must Once the root sub-volume is made, use Rsync to clone the filesystem from the previous partition to the new BTRFS partition. fc22 I am trying to install ubuntu server 22. My Disk layout: 3 500GB SSDs (2 connected to NVME and one SATA) 2 2TB HDDS (connected to SATA) What I want: RAID0 on BTRFS for my root and boot partitions (over all three ssds) To work around this, you can enable the OpenRC service from the btrfs-progs package: # rc-update add btrfs-scan boot The volume should mount correctly after a reboot. Preferably as a separate subvolume (quota support) but possible as part of the root subvolume. It always fails after some time (with disk still running) because it cannot write boot loader. snapshots/root/20201223 The only way to check BTRFS system is to use its own tool btrfs check, you must have the root volume unmounted therefore the only option is to really boot from a livecd. Every time you run nixos-rebuild switch (or nixos-rebuild boot or any other variant that rebuilds the system), NixOS will also rebuild the Grub menu based on all the derivations in /nix/var/nix/profiles and make the active one in /run/current-system the Grub default. I love the idea of being able to take snapshots of Raspbian kernel doesn't include support btrfs by default; the initial boot stages run normally, but when the kernel loads, it won't see any filesystem which it could mount - and panics. ROOTFS_TYPE=btrfs FIXED_IMAGE_SIZE=7200 It seems this fixed image size specification is for just the BtrFS partition size and does not include thee Ext4 boot partition that is also included in the SD card image. nixos root@broken / # umount /mnt root@broken / # btrfs check --repair /dev/mapper/cryptroot enabling repair mode Checking filesystem on /dev/mapper/cryptroot checking extents bad metadata [292414476288, 292414492672) crossing stripe boundary bad metadata [292414541824, 292414558208) crossing stripe boundary bad metadata Cloning tree T p . 00KiB devid 1 size 10. I wonder if this was good idea or not. I selected the custom partitioning. Důležitá je osobní a dlouhodobá zkušenost. Use btrfs as root (tested on ubuntu, could potentially try fedora as wel) Create an xfs filesytem and mount it wherever. After some searching I haven't been able to find anything in the kernel documentation which indicates how to specify a subvolume for the root. Using configuration. UUID=a74f5787-aee1-4981-b7e6-fbd3cb6ac919 / btrfs defaults 0 1 I’ve been using armbian with my rock64 for a few years. Then I tried btrfs find-root /dev/sda1 but it looked like it was depricated and after searching the new command was sudo btrfs-find-root /dev/sda1 which worked and this is the output I got:. I have created a snapshot with: [root@k1 ~]# btrfs subvolume list / ID 256 gen 2302 top level 5 path root ID 259 gen 1703 top level 256 path var/lib/portables ID 272 gen 2289 top level 256 path . btrfs is plain wrong and dangerous , this is just a stub that prints out a message and does nothing. before anybody other than root can write to it. Initially, I was using only one of the HDD’s as /home (still encrypted BTRFS). This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable More recent distributions use busybox for most commands, including mount. When you mount a partition which supports POSIX permissions and ownerships, the mount point is set to be owned by whoever mounted it - usually, root (sudo The default subvolume (root) with ID 258 is mounted as the active root file system. Clean up the old root subvols. To keep it as simple as possible, I would like to integrate the creation of a Btrfs snapshot into my upgrade-alias command, which currently looks like this: . No troubles since. If these two values in the last line match, all space on the file system has been allocated. sudo btrfs filesystem show Example Output: That means that your current default "subvolume" is the BTRFS-ROOT subvolume itself (that's the default value for BTRFS). Reply Installing a System With a Btrfs root File System; 7 Installing a System With a Btrfs root File System Oracle Linux uses XFS as the default file system, but it also supports other file systems such as ext2, ext4, and so on. You have to grant permissions and ownerships using chowm, chmod, setfacl, etc. grub options correctly for your hardware. I’m just Disk preparation. I tried to make a Fedora 34 installation where I choose my root partition as a BTRFS volume because i thought it was a good idea to use both the internal ssd and a micro sd as one partition (the ssd is 64gb and I needed to use windows so my plan was to use ~32gb for each os and half of my micro sd for fedora) but after rebooting grub takes me Change the file system for the root partition (not for boot) to btrfs manually with any editor such as vim. Starting with Proxmox VE 7. 0, BTRFS is introduced as optional selection for the root file system. Important. $ sudo btrfs restore -t 78515 -u 1 /dev/sda /tmp/a No valid Btrfs found on /dev/sda Could not open root, trying backup super checksum verify failed on 25001984 wanted 0x00000000 found 0xb6bde3e4 checksum verify failed on 25001984 wanted 0x00000000 found 0xb6bde3e4 checksum verify failed on 25001984 wanted 0x00000000 found 0xb6bde3e4 bad It should be possible to use btrfs instead of ext4 as the root file system. I'm switching to BTRFS RAID1, and for the sake of integrity, want to include /boot within the BTRFS partition. Boot your desktop with a live usb. e. 26GiB path /dev/sdc devid 2 size 10. btrfs subv del @root, btrfs subv snap @snapshots/<name of your root-snapshot> @root. Once I added the second drive and Bro i lost all my data when i try to do this. See also. 00GiB used 1. Check which device is the one you want to install Void into. (Includes changing the UUID to the new partition too) Now you have a Raspberry Pi running on BTRFS. , with btrfs as root. 02-0. To continue with the steps in this tutorial, the root file system of the Oracle Linux installation should be using Btrfs. com/jirutka/990d25662e729669b3ce (for Gentoo and syslinux) Btrfs is versatile, working on single or multiple disks and supporting a variety of RAID modes, or Profiles, not all of which are traditional RAID modes. ; base-devel: Group of packages for building software from source. The file I need a Nix expert to confirm this, but I believe you can accomplish that without putting /boot on btrfs/zfs. fstab is added to the original post, and i also update btrfs subvolume list /mnt/ result. 24 tells Debian installer to create EXT4 as root fs. Upon a successful sync to zram, any files and directories contained in /etc/ramroot/ are non-persistently overwritten to the root directory. Created a small EFI partition and then used the rest as / with btrfs. 04 system with a luks-encrypted partition which contains a LVM with a logical volume for the root filesystem that is formatted with btrfs It kept failing whenever BTRFS was made the Root partition, mounting at / along side a different filesystem set for /var results in the install failing. It's due to how BTRFS deals with nested subvolumes in general (read the Sysadmin's Guide). Btrfs sometimes btrfs cannot free space making linux unbootable and read-only in windows. Migrate the system root filesystem to /@rootfs for the primary Linux system. I have a multiboot situation consist of Debian, Fedora, OpenSUSE and KaOS. In these releases, /bin/mount is a symlink to /bin/busybox and the symlink must be named "mount", and not "mount. Thus, to install Oracle Linux with Btrfs, you must To install the driver, download and extract the latest release, right-click btrfs. rsync -avxHW / /mnt/btrfs/\@root/ Make changes to the cmdline. With EXT4 it is ok. Gets mounted as /. ; sudo: Allows executing commands as root. Now shutdown your Raspberry TL;DR: btrfs check fails because of "errors found in fs roots". create subvolumes (“@” seams to be a common name to use for the main subvolume) Now, the last remark: To make a copy of subvolume on the same btrfs partition you just need to do sudo btrfs subvolume snapshot <path to the copied root> @mynewroot (ideal, when you want to test in parallel many btrfs-based Linux distributions, but not own 1TB hard drive). (You can also use the fact that snapshots can be handled like normal directories and mv @root root-backup to keep your old root now and delete it later. I used backup before, but this time I forgot to backup for a while, and now I can’t boot from the memory card anymore. 78GiB path /dev/sda3 Shows the total size of the file system and its usage. 16. See more Btrfs has been built into the kernel (not a module) along with lzo compression/decompression as that will be used to optimize space utilization and read This is an alternative guide on using a subvolume in a Btrfs filesystem as the system's root, as an update to the original example for re-basing a Gentoo installation's root Btrfs/System Root Guide — one example for re-basing a Gentoo installation's root filesystem to use btrfs; Btrfs/Native System Root Guide — alternative guide on using a Migrating Debian from a single disk with ext4 to two disks with btrfs and RAID1. tried to recover it, but no idea what I should do. type为BTRFS_ROOT_ITEM_KEY，payload对应的数据结构为struct btrfs_root_item 。这点也可以在官方wiki[3]中得到证实。如果只想筛选某一种树的树根，可以根据btrfs_item. It is a modern copy-on-write (CoW) filesystem for Linux aimed at implementing advanced features while focusing on fault root@omvt:~# btrfs fi sh /srv/dev-disk-by-id-scsi-0QEMU_QEMU_HARDDISK_drive-scsi2-0-0-5 Label: none uuid: 92f57413-34fa-4a6c-b4a2-640a35d27281 Total devices 2 FS bytes used 144. Congratulations. And it just works perfectly. Modified 13 years, 4 months ago. img } I also tried without mentioning the subvolume, that droped me in grub rescue, which seems to suggest that having the subvolume mentioned is "a good thing". A solution ```sh btrfs device add /dev/sda3 / btrfs balance start -dconvert=raid1 -mconvert=raid1 / ``` ```sh mkdir /mnt/btrfs mount -t btrfs -o defaults,noatime,compress=no,autodefrag -L btrfsvol /mnt/btrfs btrfs quota enable /mnt/btrfs/ btrfs subvolume create /mnt/btrfs/root btrfs subvolume create /mnt/btrfs/var umount /mnt/btrfs mkdir 从内核的btrfs_read_roots()函数中，我们可以知道对于root tree而言，其btrfs_item. Fedora recently switched to btrfs as default for the root partition. 0. <mountpoint root> / btrfs subvol=@root,defaults,noatime 0 1 /etc/fstab. Try passing init= bootarg. It seems the install program automatically created a btrfs subpartition for /home as part For Btrfs, with the exception of @home/. 2 into a system with three drives - 1 SSD containing the / partition (btrfs format with default subvolumes), and 2 identical HDD’s containing /home in an encrypted BTRFS RAID1 array. after 4 attempt at building a Xenial system with a BtrFS root volume finally fits within the SD card. Without execute permission on the directory, 'other' users cannot not traverse it. drwxrwxrw- 1 root root 192 May 13 08:33 EDATA Non-root user cannot access mounted btrfs filesystem. snapshots, they are all located at the highest level (top level 5). BTRFS on Alpine Linux; Using BTRFS on Alpine Linux; Can't mount BTRFS volume using fstab; ArchWiki; Gentoo Wiki; Install Alpine on a btrfs filesystem with refind as boot BTRFS is a modern copy on write file system natively supported by the Linux kernel, implementing features such as snapshots, built-in RAID and self healing via checksums for data and metadata. It seems I needed a reinstall. Convert the partition containing the primary old Linux system from ext4 to btrfs using btrfs-convert. This example will use GPT as disk partition schema and grub(or rEFInd) as boot loader. btrfs -L root /dev/mapper/vg-root If you want to set up brtfs subvolumes, now is a good time for that. However, due to power cut issue, the boot partition got corrupted a couple times. Run a container with a bind mount into xfs: This is a workaround for. In this example I will copy an existing root filesystem onto the new btrfs raid. 02GiB used 13. 04 on a Btrfs root-partition for its snapshot functionality. The Btrfs file # mount the BTRFS root subvol $ mount /dev/sdXY mnt -o subvol=/ # set the default mounting subvol $ btrfs sub set NNN mnt # remount the BTRFS partition, it will mount the subvolume set in previous step $ umount mnt && mount /dev/sdaXY mnt # chroot into the subvolume $ arch-chroot mnt /bin/bash #inside chroot run grub-install $ grub-install - GRUB2 from other distribution cannot boot into distribution using BTRFS as root. sudo apt update && sudo apt upgrade -y && sudo flatpak update -y && sudo snap refresh sudo btrfs filesystem show / Label: 'ROOT' uuid: 52011c5e-5711-42d8-8c50-718a005ec4b3 Total devices 1 FS bytes used 10. Run the NixOS installer and install gnome. Edit fstab, bootloader, cmdline, etc. ignoredatacsums, idatacsums (since: 5. I would like to note that there is the possiblity that this problem might happen regardless of whichever partition it is assigned to. Já souborový systém Btrfs provozuji od roku 2013, tenkrát se I've installed Ubuntu 20. I was wondering if I can do the same in arch linux. However if you wish to format your second partition as btrfs before copying, and use it as the root file system, you will also need to change your GRUB configuration to look at the new partition. If I create a btrfs filesystem and follow rest of the instructions in the arch linux installation guide will my system work fine ? Are other filesystems such as zfs, xfs, f2fs supported ? It's common for Fedora this days when you format your system with btrfs to create a subvolume called root, so if you didn't find the subvol option in fstab, then omit root from subvol. Hello, I am playing with btrfs and especially its snapshot capability for my root (/) volume. No init found. If you using Windows 10 or 11 and have Secure Boot Here's an example when mounting a 10 GB xfs lvm volume in ~/experiements/xfstest when I run ubuntu with a btrfs root folder. Any advice that ultimately leads to calling fsck. The root system is using btrfs. I went to btrfs root and then kept my existing zfs pools. Steps to reproduce the issue. 11) Ignore data checksum verification. base: Minimal package set defining a basic Arch Linux installation. txt file about the new root FS being BTRFS. The driver is signed, so should work out of the box on modern versions of Windows. Nix installation. See Btrfs Wiki: Conversion_from_Ext3. " Then adds "One thing that caught my attention in openSUSE 13. My current setup with ext4 is still there so I can continue to Prepend the root filesystem line with a hash (#), to comment out it: #UUID=1fe54331-f99a-4ef5-9bd4-a4fff6223e87 / ext4 errors=remount-ro 0 1. objectid来判断。在此 I'm trying to set up a btrfs seed device as root partition. / # btrfs root filesystem mounted as /mnt/ssd/ @ # a subvolume I use as the root filesystem (mounted as /) @backups @-20161215-1-working # a snapshot of @ just in case Let's suppose I want to mess with my system. The mount command shows the device that's mounted as the root file system and indicates the subvolume ID (258): sudo mount|grep 'on / ' /dev/sda2 on / type btrfs (rw,relatime,seclabel,space_cache,subvolid=258,subvol=/root) The root tree also has a directory to map subvolume names to struct btrfs_root_items in the root tree. The basic idea here, is that nixos-generate-config --root /mnt generates a configuration. You basically do a write/read copy of your read-only copy Reboot and your done. pjtn qct wmtjqa youiivme ouz josx exmn rlawya uybh fpc dpjo vlpf oarem evfw yxkgrdu