linux df -h not showing some info

I have Ubuntu 20.04 linux and I create a second disk, and second filesystem. Right now when I want to see info my second filesystem df is not showing. I use default mount specification.

df -ah
Filesystem                         Size  Used Avail Use% Mounted on
sysfs                                 0     0     0    - /sys
proc                                  0     0     0    - /proc
udev                               3.9G     0  3.9G   0% /dev
devpts                                0     0     0    - /dev/pts
tmpfs                              795M  1.6M  794M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   49G   13G   34G  27% /
securityfs                            0     0     0    - /sys/kernel/security
tmpfs                              3.9G     0  3.9G   0% /dev/shm
tmpfs                              5.0M     0  5.0M   0% /run/lock
tmpfs                              3.9G     0  3.9G   0% /sys/fs/cgroup
cgroup2                               0     0     0    - /sys/fs/cgroup/unified
cgroup                                0     0     0    - /sys/fs/cgroup/systemd
pstore                                0     0     0    - /sys/fs/pstore
none                                  0     0     0    - /sys/fs/bpf
cgroup                                0     0     0    - /sys/fs/cgroup/freezer
cgroup                                0     0     0    - /sys/fs/cgroup/hugetlb
cgroup                                0     0     0    - /sys/fs/cgroup/cpu,cpuacct
cgroup                                0     0     0    - /sys/fs/cgroup/net_cls,net_prio
cgroup                                0     0     0    - /sys/fs/cgroup/pids
cgroup                                0     0     0    - /sys/fs/cgroup/memory
cgroup                                0     0     0    - /sys/fs/cgroup/devices
cgroup                                0     0     0    - /sys/fs/cgroup/blkio
cgroup                                0     0     0    - /sys/fs/cgroup/cpuset
cgroup                                0     0     0    - /sys/fs/cgroup/perf_event
cgroup                                0     0     0    - /sys/fs/cgroup/rdma
systemd-1                             0     0     0    - /proc/sys/fs/binfmt_misc
hugetlbfs                             0     0     0    - /dev/hugepages
mqueue                                0     0     0    - /dev/mqueue
tracefs                               0     0     0    - /sys/kernel/tracing
debugfs                               0     0     0    - /sys/kernel/debug
configfs                              0     0     0    - /sys/kernel/config
fusectl                               0     0     0    - /sys/fs/fuse/connections
/dev/loop0                          71M   71M     0 100% /snap/lxd/21029
/dev/sda2                          976M  299M  610M  33% /boot
/dev/loop1                          56M   56M     0 100% /snap/core18/2128
tmpfs                              795M  1.6M  794M   1% /run/snapd/ns
/dev/loop4                          62M   62M     0 100% /snap/core20/1081
/dev/loop5                          68M   68M     0 100% /snap/lxd/21545
nsfs                                  0     0     0    - /run/snapd/ns/lxd.mnt
/dev/mapper/elk--vg-elk--lv           -     -     -    - /mnt/elk
/dev/loop6                          62M   62M     0 100% /snap/core20/1169
/dev/loop7                          33M   33M     0 100% /snap/snapd/13270
/dev/loop2                          33M   33M     0 100% /snap/snapd/13640
/dev/loop8                          56M   56M     0 100% /snap/core18/2246
tmpfs                              795M     0  795M   0% /run/user/1000

/mnt/elk is my second filesystem and it's showing - - -

UUID=764818a1-03bd-4f7a-       /mnt/elk        ext4    defaults 0 1

this is my fstab file line

when I switch user root df is showing /mnt/elk filesystem information

df -h
Filesystem                         Size  Used Avail Use% Mounted on
udev                               3.9G     0  3.9G   0% /dev
tmpfs                              795M  1.6M  794M   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv   49G   13G   34G  27% /
tmpfs                              3.9G     0  3.9G   0% /dev/shm
tmpfs                              5.0M     0  5.0M   0% /run/lock
tmpfs                              3.9G     0  3.9G   0% /sys/fs/cgroup
/dev/loop0                          71M   71M     0 100% /snap/lxd/21029
/dev/sda2                          976M  299M  610M  33% /boot
/dev/loop1                          56M   56M     0 100% /snap/core18/2128
/dev/loop4                          62M   62M     0 100% /snap/core20/1081
/dev/loop5                          68M   68M     0 100% /snap/lxd/21545
/dev/mapper/elk--vg-elk--lv        196G   13G  174G   7% /mnt/elk
/dev/loop6                          62M   62M     0 100% /snap/core20/1169
/dev/loop7                          33M   33M     0 100% /snap/snapd/13270
/dev/loop2                          33M   33M     0 100% /snap/snapd/13640
/dev/loop8                          56M   56M     0 100% /snap/core18/2246
tmpfs                              795M     0  795M   0% /run/user/1000

it's look like relevant permission but there is no any restriction


Following discussion in comments, steps to follow in such a situation:

  • check read/write settings first with mount
  • check also that the path is accessible to the user, and correct this if needed.