Recommended root FS passno is 1 (current is 0)

[tuxaholic]

Hi all,

I was creating a swap file using this guide and when I ran sudo findmnt --verify --verbose I got this warning for my root file-system:

/
   [ ] target exists
   [ ] VFS options: noatime
   [ ] FS options: subvol=/@,autodefrag,compress=zstd
   [ ] UUID=10840302-2838-4187-842a-eee8f883ed50 translated to /dev/sda2
   [ ] source /dev/sda2 exists
   [ ] FS type is btrfs
   [W] recommended root FS passno is 1 (current is 0)

I have not touched that line, but rather appended the two at the bottom:

UUID=5DCC-BB8B                            /boot/efi      vfat    umask=0077 0 2
UUID=10840302-2838-4187-842a-eee8f883ed50 /              btrfs   subvol=/@,defaults,noatime,autodefrag,compress=zstd 0 0
UUID=10840302-2838-4187-842a-eee8f883ed50 /home          btrfs   subvol=/@home,defaults,noatime,autodefrag,compress=zstd 0 0
UUID=10840302-2838-4187-842a-eee8f883ed50 /var/cache     btrfs   subvol=/@cache,defaults,noatime,autodefrag,compress=zstd 0 0
UUID=10840302-2838-4187-842a-eee8f883ed50 /var/log       btrfs   subvol=/@log,defaults,noatime,autodefrag,compress=zstd 0 0
UUID=10840302-2838-4187-842a-eee8f883ed50 /swap          btrfs   subvol=/@swap,defaults,noatime 0 0
/swap/swapfile                            none           swap    defaults 0 0

What is this trying to warn me about? Should I change the passno of the root file system to 1 and why?

[pebcak]

Traditional filesystems need to run their respective fsck utility in case the filesystem was not unmounted cleanly and the log needs to be replayed before mount. This is not needed for btrfs. You should set fs_passno to 0.

https://btrfs.wiki.kernel.org/index.php/FAQ#When_will_Btrfs_have_a_fsck_like_tool.3F

[dalto]

@tuxaholic

Should I change the passno of the root file system to 1 and why?

No, running fsck on btrfs is pointless. If you try it just runs a script that does more or less nothing.

[tuxaholic]

Thanks for that link. Lots of useful info in that reference.