Question about /etc/fstab

In Fedora, my /etc/fstab looked like this:


> cat /mnt/backups/fedora/etc/fstab


#
# /etc/fstab
# Created by anaconda on Sat Jan  5 20:34:23 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk/'.
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info.
#
# After editing this file, run 'systemctl daemon-reload' to update systemd
# units generated from this file.
#
**UUID=7761e5db-3acd-43c2-a7ab-1e60026fe5aa   /       btrfs   subvol=root          0 0**
UUID=33166983-6571-4f01-8fac-3bce43a06770   /boot   ext4    defaults             1 2
UUID=7C4B-378E                          /boot/efi   vfat    umask=0077,shortname=winnt   0 2
UUID=7761e5db-3acd-43c2-a7ab-1e60026fe5aa   /home   btrfs   subvol=home          0 0
UUID=07b5a785-b1df-493e-a63b-5e6b533a0c10   /mnt/backups    btrfs   discard      0 0

In openSUSE Tumbleweed, it looks like this:


> cat /etc/fstab
**UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /                       btrfs  defaults                      0  0**
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /.snapshots             btrfs  subvol=/@/.snapshots          0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /var                    btrfs  subvol=/@/var                 0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /usr/local              btrfs  subvol=/@/usr/local           0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /tmp                    btrfs  subvol=/@/tmp                 0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /srv                    btrfs  subvol=/@/srv                 0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /root                   btrfs  subvol=/@/root                0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /opt                    btrfs  subvol=/@/opt                 0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /home                   btrfs  subvol=/@/home                0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /boot/grub2/x86_64-efi  btrfs  subvol=/@/boot/grub2/x86_64-efi  0  0
UUID=8e2eab35-ae1a-4e73-85ef-db7bf3142a2c  /boot/grub2/i386-pc     btrfs  subvol=/@/boot/grub2/i386-pc  0  0
UUID=16C3-AD52                             /boot/efi               vfat   utf8                          0  2
UUID=07b5a785-b1df-493e-a63b-5e6b533a0c10  /mnt/backups            btrfs  defaults                      0  0

The entry for / was generated by the installer in both cases. Why are the mount options for / different?

Thanks,
Gene

openSUSE assigns the rootfs as primary/default subvolume. Rolling back to a snapshot maintains this property, another read/write snapshot of the rootfs subvolume becomes the default. This way /etc/fstab doesn’t need to be updated to reflect this new state.

Thanks for the info.

Gene