Issue with Reserved Space Showing Incorrectly in Netdata Disks Charts for One Partition

Help
, ,
1

Summary:
I have created my ext4 file systems without reserved space for root (reserved block count) during the Debian12 installation using the -m 0 option with mkfs.ext4. This configuration is correctly applied to all partitions, and I am able to see the 0% reserved space for all my partitions

Partition List:

root@DEB-ZBOXMI35-GXXXX472XXXXX:~# lsblk 
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
nvme0n1     259:0    0 232.9G  0 disk 
├─nvme0n1p1 259:1    0   512M  0 part /boot/efi
├─nvme0n1p2 259:2    0    18G  0 part /
├─nvme0n1p3 259:3    0     6G  0 part /opt/debian12/log
└─nvme0n1p4 259:4    0 208.4G  0 part /var/lib/docker

Verification of Reserved Block Count:
All partitions show a reserved block count of 0:

root@DEB-ZBOXMI35-GXXXX472XXXXX:~# sudo dumpe2fs -h /dev/nvme0n1p2 | grep -i "reserved block count"
dumpe2fs 1.47.0 (5-Feb-2023)
Reserved block count:     0

root@DEB-ZBOXMI35-GXXXX472XXXXX:~# sudo dumpe2fs -h /dev/nvme0n1p3 | grep -i "reserved block count"
dumpe2fs 1.47.0 (5-Feb-2023)
Reserved block count:     0

root@DEB-ZBOXMI35-GXXXX472XXXXX:~# sudo dumpe2fs -h /dev/nvme0n1p4 | grep -i "reserved block count"
dumpe2fs 1.47.0 (5-Feb-2023)
Reserved block count:     0

Netdata Configuration:

Here is my current Netdata configuration for disk space:

[plugin:proc:diskspace]
    update every = 60
    exclude space metrics on paths = /proc/* /sys/* /var/run/user/* /run/user/* /var/lib/docker/* /dev /dev/shm /run /run/* 
    inodes usage for all disks = no

[plugin:proc:/proc/diskstats]
    exclude disks = loop* ram* boot rootfs rex-kmshare ext4
    merged operations for all disks = no
    backlog for all disks = no
    i/o time for all disks = no
    enable new disks detected at runtime = no

[plugin:proc:/proc/diskstats:sda]
    enable = yes
    enable performance metrics = auto
    bandwidth = auto
    operations = auto
    merged operations = no
    queued operations = auto
    utilization percentage = auto
    extended operations = no

[plugin:proc:/proc/diskstats:nvme0n1]
    enable = yes
    enable performance metrics = auto
    bandwidth = auto
    operations = auto
    merged operations = no
    queued operations = auto
    utilization percentage = auto
    extended operations = no

In Netdata, the reserved space for root is correctly shown as 0% for 2 partitions ( /root & /var/lib/docker) out of 3 partitions.

2024_06_04_0vt_Kleki
2024_06_04_0vt_Kleki1794×343 40.3 KB

2024_06_04_0vv_Kleki
2024_06_04_0vv_Kleki1827×365 48 KB

Issue:

But the reserved space for root is incorrectly displays as 0.2 for one partition ( /opt/debian12/log) but the Internally its value is set to 0 only.

2024_06_04_0wf_Kleki
2024_06_04_0wf_Kleki1805×364 47.7 KB

  1. Manual Calculation of Reserved Space:
    Manually calculated reserved space to cross-verify the displayed value:
root@DEB-ZBOXMI35-GXXXX472XXXXX:~# lsblk
NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
nvme0n1     259:0    0 232.9G  0 disk 
├─nvme0n1p1 259:1    0   512M  0 part /boot/efi
├─nvme0n1p2 259:2    0    18G  0 part /
├─nvme0n1p3 259:3    0     6G  0 part /opt/debian12/log
└─nvme0n1p4 259:4    0 208.4G  0 part /var/lib/docker

root@DEB-ZBOXMI35-GXXXX472XXXXX:~# sudo dumpe2fs -h /dev/nvme0n1p3 | grep -i "reserved block count"
dumpe2fs 1.47.0 (5-Feb-2023)
Reserved block count:     0
root@DEB-ZBOXMI35-GXXXX472XXXXX:~#

Confirmed that the reserved block count is indeed 0.

Request for Assistance:

I am aware that we can hide this dimension from Netdata charts, but I don’t want to hide it. I want to understand the underlying mechanism and why it is showing 0.2% for this partition despite the actual reserved space being set to 0%.

Any guidance on resolving this discrepancy would be greatly appreciated.

Thank you in advance for your help!