btop
btop copied to clipboard
aristocratos
[BUG] Ubuntu on ZFS has strange fstab and mount points
This is more meant to be informational rather than a real bug report, but I think there will be progressively more systems running on top of ZFS as time goes on, due to the potential ease of instant snapshotting and recovery from system issues. So this is just something to think about.
My system is Ubuntu 21.10, upgraded from 21.04 and was installed with the ZFS-on-root option. So the disks box in BpyTOP or BTOP ends up being sort of useless regardless of whether "use fstab" is enabled or disabled. With fstab, it shows only EFI and GRUB entries, because that's all that appears in fstab. Without fstab it shows a long list of different things, many of which have the same "size" because they exist on the same ZFS filesystem. Most would be irrelevant to most users as independent listings, and the free/used is redundant with other entries.
I've tried looking at the mount points and the output of lsblk and the fstab, but... I don't know exactly how you might go about consolidating this type of system into a more sensible collection of "disks" in the disks box. But I'm pretty sure this will become more and more of an issue as time goes on.
This is what my Nautilus shows when I go into "Other Locations":
The "rpool" and "bpool" are not mountable (error: unknown filesystem type 'zfs_member'), so the fact that they are displayed at all in a file browser is probably fairly useless. But the thing labeled "Computer" is the root filesystem on th 4TB SATA drive that Ubuntu is installed on, and the one labeled "MacVM" is an NVMe drive.
Oh, and the whole main drive is encrypted, so that complicates the output.
Anyway, I don't know exactly how to solve this, but I figure there must be a relatively simple way to tease out just the main "volumes" and their overall sizes and used/free space, even on a system like this.
zfs list gives this mess:
NAME USED AVAIL REFER MOUNTPOINT
bpool 397M 1.36G 96K /boot
bpool/BOOT 394M 1.36G 96K none
bpool/BOOT/ubuntu_bcqdgs 394M 1.36G 161M /boot
rpool 553G 2.97T 192K /
rpool/ROOT 22.2G 2.97T 192K none
rpool/ROOT/ubuntu_bcqdgs 22.2G 2.97T 5.92G /
rpool/ROOT/ubuntu_bcqdgs/srv 352K 2.97T 192K /srv
rpool/ROOT/ubuntu_bcqdgs/usr 7.52M 2.97T 192K /usr
rpool/ROOT/ubuntu_bcqdgs/usr/local 7.34M 2.97T 3.66M /usr/local
rpool/ROOT/ubuntu_bcqdgs/var 12.2G 2.97T 192K /var
rpool/ROOT/ubuntu_bcqdgs/var/games 192K 2.97T 192K /var/games
rpool/ROOT/ubuntu_bcqdgs/var/lib 11.8G 2.97T 7.90G /var/lib
rpool/ROOT/ubuntu_bcqdgs/var/lib/AccountsService 1.30M 2.97T 324K /var/lib/AccountsService
rpool/ROOT/ubuntu_bcqdgs/var/lib/NetworkManager 4.74M 2.97T 624K /var/lib/NetworkManager
rpool/ROOT/ubuntu_bcqdgs/var/lib/apt 108M 2.97T 81.8M /var/lib/apt
rpool/ROOT/ubuntu_bcqdgs/var/lib/dpkg 493M 2.97T 104M /var/lib/dpkg
rpool/ROOT/ubuntu_bcqdgs/var/log 430M 2.97T 205M /var/log
rpool/ROOT/ubuntu_bcqdgs/var/mail 192K 2.97T 192K /var/mail
rpool/ROOT/ubuntu_bcqdgs/var/snap 9.04M 2.97T 2.90M /var/snap
rpool/ROOT/ubuntu_bcqdgs/var/spool 3.04M 2.97T 428K /var/spool
rpool/ROOT/ubuntu_bcqdgs/var/www 192K 2.97T 192K /var/www
rpool/USERDATA 530G 2.97T 192K /
rpool/USERDATA/kris_w8vqdt 530G 2.97T 484G /home/kris
rpool/USERDATA/newuser_p5y9up 77.3M 2.97T 76.7M /home/newuser
rpool/USERDATA/root_w8vqdt 6.18M 2.97T 2.24M /root
rpool/keystore 518M 2.97T 48.1M -
You can see here that the "used" is different on each line, but the "avail" is identical for each of the sub-pools that are part of the main pool.
This output can basically be trimmed down to this (with zfs list | grep -v "pool/"):
NAME USED AVAIL REFER MOUNTPOINT
bpool 397M 1.36G 96K /boot
rpool 553G 2.97T 192K /
And those are essentially the only relevant "volumes" with their used/free space.
Of course every system that uses ZFS-on-root will probably have different naming conventions for the basic pools. So there must be a more generic command that can trim it down to just the parent ZFS pools.
Oh, here, this makes more sense (zpool list):
NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
bpool 1.88G 398M 1.49G - - 1% 20% 1.00x ONLINE -
rpool 3.62T 553G 3.09T - - 5% 14% 1.00x ONLINE -
Output of cat /etc/fstab:
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# /boot/efi was on /dev/sda1 during installation
UUID=5742-EF92 /boot/efi vfat umask=0022,fmask=0022,dmask=0022 0 1
/boot/efi/grub /boot/grub none defaults,bind 0 0
/dev/mapper/cryptoswap none swap sw 0 0
Output from lsblk:
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 164.8M 1 loop /snap/gnome-3-28-1804/161
loop1 7:1 0 61.3M 1 loop /snap/authy/6
loop2 7:2 0 61.5M 1 loop /snap/authy/7
loop3 7:3 0 144.6M 1 loop /snap/chromium/1810
loop4 7:4 0 253.2M 1 loop /snap/brave/138
loop5 7:5 0 55.5M 1 loop /snap/core18/2246
loop6 7:6 0 219M 1 loop /snap/gnome-3-34-1804/72
loop7 7:7 0 51M 1 loop /snap/snap-store/547
loop8 7:8 0 15.5M 1 loop /snap/whitesur-gtk-theme/147
loop9 7:9 0 15.6M 1 loop /snap/whitesur-gtk-theme/155
loop10 7:10 0 213.8M 1 loop /snap/code/83
loop11 7:11 0 99.4M 1 loop /snap/core/11798
loop12 7:12 0 85.7M 1 loop /snap/standard-notes/77
loop13 7:13 0 54.2M 1 loop /snap/snap-store/558
loop14 7:14 0 147.8M 1 loop /snap/chromium/1827
loop15 7:15 0 242.3M 1 loop /snap/gnome-3-38-2004/76
loop16 7:16 0 247.9M 1 loop /snap/gnome-3-38-2004/87
loop17 7:17 0 99.4M 1 loop /snap/core/11993
loop18 7:18 0 4K 1 loop /snap/bare/5
loop19 7:19 0 219M 1 loop /snap/gnome-3-34-1804/77
loop20 7:20 0 253.8M 1 loop /snap/brave/139
loop21 7:21 0 55.5M 1 loop /snap/core18/2253
loop22 7:22 0 43.3M 1 loop /snap/snapd/14295
loop23 7:23 0 222.2M 1 loop /snap/code/82
loop24 7:24 0 85.7M 1 loop /snap/standard-notes/76
loop25 7:25 0 42.2M 1 loop /snap/snapd/14066
loop26 7:26 0 61.8M 1 loop /snap/core20/1242
loop27 7:27 0 61.9M 1 loop /snap/core20/1270
loop28 7:28 0 65.2M 1 loop /snap/gtk-common-themes/1519
loop29 7:29 0 65.1M 1 loop /snap/gtk-common-themes/1515
sda 8:0 0 3.6T 0 disk
ââsda1 8:1 0 512M 0 part /boot/efi
ââsda2 8:2 0 2G 0 part
â ââcryptoswap 253:1 0 2G 0 crypt [SWAP]
ââsda3 8:3 0 2G 0 part
ââsda4 8:4 0 3.6T 0 part
zd0 230:0 0 500M 0 disk
ââkeystore-rpool 253:0 0 484M 0 crypt /run/keystore/rpool
nvme0n1 259:0 0 476.9G 0 disk
âânvme0n1p1 259:1 0 476.9G 0 part /media/kris/MacVM
Output from mount:
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=11205548k,nr_inodes=2801387,mode=755,inode64)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,noexec,relatime,size=2249004k,mode=755,inode64)
/dev/mapper/keystore-rpool on /run/keystore/rpool type ext4 (rw,relatime,stripe=2)
rpool/ROOT/ubuntu_bcqdgs on / type zfs (rw,relatime,xattr,posixacl)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,inode64)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k,inode64)
cgroup2 on /sys/fs/cgroup type cgroup2 (rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime)
none on /sys/fs/bpf type bpf (rw,nosuid,nodev,noexec,relatime,mode=700)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=29,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=26740)
mqueue on /dev/mqueue type mqueue (rw,nosuid,nodev,noexec,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime,pagesize=2M)
tracefs on /sys/kernel/tracing type tracefs (rw,nosuid,nodev,noexec,relatime)
fusectl on /sys/fs/fuse/connections type fusectl (rw,nosuid,nodev,noexec,relatime)
configfs on /sys/kernel/config type configfs (rw,nosuid,nodev,noexec,relatime)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,nosuid,nodev,noexec,relatime)
rpool/USERDATA/newuser_p5y9up on /home/newuser type zfs (rw,relatime,xattr,posixacl)
rpool/USERDATA/kris_w8vqdt on /home/kris type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/usr/local on /usr/local type zfs (rw,relatime,xattr,posixacl)
rpool/USERDATA/root_w8vqdt on /root type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/srv on /srv type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/games on /var/games type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/lib on /var/lib type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/log on /var/log type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/spool on /var/spool type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/snap on /var/snap type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/mail on /var/mail type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/www on /var/www type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/lib/NetworkManager on /var/lib/NetworkManager type zfs (rw,relatime,xattr,posixacl)
/var/lib/snapd/snaps/gnome-3-28-1804_161.snap on /snap/gnome-3-28-1804/161 type squashfs (ro,nodev,relatime,x-gdu.hide)
rpool/ROOT/ubuntu_bcqdgs/var/lib/AccountsService on /var/lib/AccountsService type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/lib/apt on /var/lib/apt type zfs (rw,relatime,xattr,posixacl)
rpool/ROOT/ubuntu_bcqdgs/var/lib/dpkg on /var/lib/dpkg type zfs (rw,relatime,xattr,posixacl)
/var/lib/snapd/snaps/authy_6.snap on /snap/authy/6 type squashfs (ro,nodev,relatime,x-gdu.hide)
tmpfs on /run/qemu type tmpfs (rw,nosuid,nodev,relatime,mode=755,inode64)
bpool/BOOT/ubuntu_bcqdgs on /boot type zfs (rw,nodev,relatime,xattr,posixacl)
/dev/sda1 on /boot/efi type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/dev/sda1 on /boot/grub type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro)
/var/lib/snapd/snaps/authy_7.snap on /snap/authy/7 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/chromium_1810.snap on /snap/chromium/1810 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/brave_138.snap on /snap/brave/138 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core18_2246.snap on /snap/core18/2246 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gnome-3-34-1804_72.snap on /snap/gnome-3-34-1804/72 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/snap-store_547.snap on /snap/snap-store/547 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/whitesur-gtk-theme_147.snap on /snap/whitesur-gtk-theme/147 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/whitesur-gtk-theme_155.snap on /snap/whitesur-gtk-theme/155 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/code_83.snap on /snap/code/83 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core_11798.snap on /snap/core/11798 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/standard-notes_77.snap on /snap/standard-notes/77 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/snap-store_558.snap on /snap/snap-store/558 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/chromium_1827.snap on /snap/chromium/1827 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gnome-3-38-2004_76.snap on /snap/gnome-3-38-2004/76 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gnome-3-38-2004_87.snap on /snap/gnome-3-38-2004/87 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core_11993.snap on /snap/core/11993 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/bare_5.snap on /snap/bare/5 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gnome-3-34-1804_77.snap on /snap/gnome-3-34-1804/77 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/brave_139.snap on /snap/brave/139 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core18_2253.snap on /snap/core18/2253 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/snapd_14295.snap on /snap/snapd/14295 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/code_82.snap on /snap/code/82 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/standard-notes_76.snap on /snap/standard-notes/76 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/snapd_14066.snap on /snap/snapd/14066 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core20_1242.snap on /snap/core20/1242 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/core20_1270.snap on /snap/core20/1270 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gtk-common-themes_1519.snap on /snap/gtk-common-themes/1519 type squashfs (ro,nodev,relatime,x-gdu.hide)
/var/lib/snapd/snaps/gtk-common-themes_1515.snap on /snap/gtk-common-themes/1515 type squashfs (ro,nodev,relatime,x-gdu.hide)
none on /sys/fs/cgroup/net_cls type cgroup (rw,relatime,net_cls)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=2249000k,nr_inodes=562250,mode=700,uid=1000,gid=1000,inode64)
gvfsd-fuse on /run/user/1000/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
portal on /run/user/1000/doc type fuse.portal (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
tmpfs on /run/snapd/ns type tmpfs (rw,nosuid,nodev,noexec,relatime,size=2249004k,mode=755,inode64)
nsfs on /run/snapd/ns/snap-store.mnt type nsfs (rw)
pcloud_81a7ec981a9f6aba47a163c15ee59c47 on /tmp/.mount_pcloudifcTgg type fuse.pcloud_81a7ec981a9f6aba47a163c15ee59c47 (ro,nosuid,nodev,relatime,user_id=1000,group_id=1000)
pCloud.fs on /home/kris/pCloudDrive type fuse (rw,nosuid,nodev,relatime,user_id=1000,group_id=1000)
/dev/nvme0n1p1 on /media/kris/MacVM type ext4 (rw,nosuid,nodev,relatime,errors=remount-ro,uhelper=udisks2)
So, long story short you could probably show something more useful in "disks" on any system where you detect ZFS-on-root by switching to using the output of zpool list with the associated mount points as names. My system would just show "/boot" and "/" (root) as relevant volumes in the disks box if you took this approach.
Thoughts?
Something like this might be easier to detect with ZFS. Just show the pools, not the datasets within the pools.
$ zpool list -o name,size,alloc
NAME SIZE ALLOC
bpool 2G 1.69G
rpool 56G 19.6G
Gives you the name of the pool, the size and how much is used.
To get the data in a less human readable (better for scripting, etc):
$ zpool list -o name,size,alloc -H -p
bpool 2147483648 1812520960
rpool 60129542144 21005828096
BTW - /etc/fstab does not even need to reference ZFS stuff, so btop does not see anything related to ZFS for me. This is my /etc/fstab:
$ cat /etc/fstab
/dev/disk/by-uuid/517E-F751 /boot/efi vfat defaults 0 0
The only disk BTOP detects is the EFI partition.
I think this issue can be closed as btop can detect ZFS without any problems now.
