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#1 2024-11-24 01:05:17
- AidanFisher
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- Registered: 2024-11-24
- Posts: 3
[SOLVED] BTRFS Sub-volume mounting
I've been using Arch intermittently for the past 5 years. Recently, I decided to return to Arch and performed a fresh installation using the btrfs file system, whereas I previously used ext4. Everything was working great until I decided to delve into the btrfs snapshot system, which, correct me if I'm wrong, would allow me to revert my system to a previous state if an update caused a malfunction or if I made a system breaking change.
I installed snapper and followed some guidance from the Snapper page on the wiki. Under "Create a new configuration" section I followed this
Note: If you are using the suggested Btrfs partition layout from archinstall then the @.snapshots subvolume will already be mounted to /.snapshots, and the snapper create-config command will fail [1]. To use the @.snapshots subvolume for Snapper backups, do the following:
- Unmount the @.snapshots subvolume and delete the existing mountpoint.
- Create the Snapper config.
- Delete the subvolume created by Snapper.
- Re-create the /.snapshots mount point and re-mount the @.snapshots subvolume.
Upon reaching the step to "re-mount the @.snapshots subvolume," I checked my fstab to make sure everything looked okay and found it completely empty. This led me down a rabbit hole of trying to understand how mounting btrfs subvolumes works with btrfs.
I guess I'm having a hard time understanding where my mountpoints are defined and how to define the /.snapshot to @.snapshot subvolume mount.
I apologize for any formatting issues in this post this is my first time in the years that I've used arch that I have posted on the forums.
Last edited by AidanFisher (2024-11-24 18:22:24)
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#2 2024-11-24 01:28:03
- Head_on_a_Stick
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- From: The Wirral
- Registered: 2014-02-20
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Re: [SOLVED] BTRFS Sub-volume mounting
I checked my fstab to make sure everything looked okay and found it completely empty
That sounds unlikely, btrfs uses that file. Some configuration can be performed from the bootloader though.
Did you use archinstall? If so then please share the full log.
Please also share the full output of
findmnt
cat /proc/cmdlineThanks.
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#3 2024-11-24 02:02:05
- AidanFisher
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- Registered: 2024-11-24
- Posts: 3
Re: [SOLVED] BTRFS Sub-volume mounting
I did use archinstall but it seems that the logs arent there anymore.
Output of findmnt
➜ ~ findmnt
TARGET SOURCE FSTYPE OPTIONS
/ /dev/nvme0n1p2[/@] btrfs rw,relatime,ssd,discard=async,space_cache=v2,subvolid=256,subvol=/@
├─/proc proc proc rw,nosuid,nodev,noexec,relatime
│ └─/proc/sys/fs/binfmt_misc systemd-1 autofs rw,relatime,fd=38,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=5703
│ └─/proc/sys/fs/binfmt_misc binfmt_misc binfmt_misc rw,nosuid,nodev,noexec,relatime
├─/sys sys sysfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/firmware/efi/efivars efivarfs efivarfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/kernel/security securityfs securityfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/fs/cgroup cgroup2 cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot
│ ├─/sys/fs/pstore pstore pstore rw,nosuid,nodev,noexec,relatime
│ ├─/sys/fs/bpf bpf bpf rw,nosuid,nodev,noexec,relatime,mode=700
│ ├─/sys/kernel/debug debugfs debugfs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/kernel/tracing tracefs tracefs rw,nosuid,nodev,noexec,relatime
│ ├─/sys/fs/fuse/connections fusectl fusectl rw,nosuid,nodev,noexec,relatime
│ └─/sys/kernel/config configfs configfs rw,nosuid,nodev,noexec,relatime
├─/dev dev devtmpfs rw,nosuid,relatime,size=16203032k,nr_inodes=4050758,mode=755,inode64
│ ├─/dev/shm tmpfs tmpfs rw,nosuid,nodev,inode64
│ ├─/dev/pts devpts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000
│ ├─/dev/hugepages hugetlbfs hugetlbfs rw,nosuid,nodev,relatime,pagesize=2M
│ └─/dev/mqueue mqueue mqueue rw,nosuid,nodev,noexec,relatime
├─/run run tmpfs rw,nosuid,nodev,relatime,mode=755,inode64
│ ├─/run/credentials/systemd-udev-load-credentials.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-journald.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-network-generator.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-tmpfiles-setup-dev-early.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-sysusers.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-tmpfiles-setup-dev.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-sysctl.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-vconsole-setup.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-tmpfiles-setup.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-resolved.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ ├─/run/credentials/systemd-networkd.service tmpfs tmpfs ro,nosuid,nodev,noexec,relatime,nosymfollow,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
│ └─/run/user/1000 tmpfs tmpfs rw,nosuid,nodev,relatime,size=3243116k,nr_inodes=810779,mode=700,uid=1000,gid=1000,inode64
│ └─/run/user/1000/doc portal fuse.portal rw,nosuid,nodev,relatime,user_id=1000,group_id=1000
├─/boot systemd-1 autofs rw,relatime,fd=52,pgrp=1,timeout=120,minproto=5,maxproto=5,direct,pipe_ino=14068
└─/tmp tmpfs tmpfs rw,nosuid,nodev,nr_inodes=1048576,inode64output of cat /proc/cmdline
initrd=\initramfs-linux.img root=PARTUUID=534a705b-a892-4264-864e-09c37d2cd871 zswap.enabled=0 rootflags=subvol=@ rw rootfstype=btrfsOffline
#4 2024-11-24 09:33:58
- Head_on_a_Stick
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- From: The Wirral
- Registered: 2014-02-20
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Re: [SOLVED] BTRFS Sub-volume mounting
The only subvolume mounted is the main root subvolume (@), there are no snapshot subvolumes mounted.
Try mounting the main partition to find other subvolumes, like this:
mount /dev/nvme0n1p2 /mnt
btrfs subvolume list /mnt
umount /mntShare the output of the middle command here, thanks.
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#5 2024-11-24 14:55:11
- AidanFisher
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- Registered: 2024-11-24
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Re: [SOLVED] BTRFS Sub-volume mounting
Since it was a brand-new installation, I opted for a fresh install last night. It appears something went wrong during my initial installation because now all my subvolumes are defined in my fstab on this new setup. Interestingly, last night, when the Arch installation attempted to configure PipeWire, an error occurred, halting the archinstall script. After retrying the installation without a sound server, it completed successfully.
This may have had something to do with me not having the sof-firmware package installed.
I believe what happened is that last week, when I performed this installation, I didn't notice it had errored out, in the past I generally didn't use the archinstall script in the past, and simply rebooted the computer. I recall that when I logged into the tty, there was no home directory defined for my user account and a few other things werent set up. I manually fixed those issues and proceeded with installing my desktop environment and other components.
This new installation with the archinstall script worked well and I just installed and configured PipeWire after the fact.
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