System Monitor report incorrect 'Available' disk size and calculates wrong 'Used%'

[akavalov]

Expected behaviour

I am running System Monitor 3.38.0 on Cinnamon. Not sure this is the right place to report the observation.
System Monitor must report correct 'Available' disk size and calculates correct 'Used%', It is not.

Actual behaviour

System Monitor report incorrect 'Available' disk size and calculates wrong 'Used%'
Please refer to the enclosed snapshots.
I have two similarly set up mounts, both are btrfs-raid1 with 2 disks over luks. For one of them /home System Monitor shows correct 'Available' value and calculates correct 'Used%'. For the other /mnt/backup it shows Available=0 and Used=100% which is wrong.

MATE general version

I am on Cinnamon.

Linux Distribution

Linux 5.10.9-201.fc33.x86_64 #1 SMP Wed Jan 20 16:56:23 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

Link to bugreport of your Distribution (requirement)

https://bugzilla.redhat.com/show_bug.cgi?id=1919679

[rbuj]

Please, submit gnome-system-monitor bugs at https://gitlab.gnome.org/GNOME/gnome-system-monitor/-/issues

[akavalov]

Thanks, done here:
https://gitlab.gnome.org/GNOME/gnome-system-monitor/-/issues/174

[rbuj]

however, I was unable to reproduce your problem in either gnome-system-monitor or mate-system-monitor.

Test: create different/equal files at mount points /mnt/test and /mnt/backup and check the displayed values:

head -c 4GB /dev/urandom > /mnt/test/test.txt
head -c 4GB /dev/urandom > /mnt/backup/test.txt

head -c 4GB /dev/urandom > /mnt/test/test.txt
head -c 2GB /dev/urandom > /mnt/backup/test.txt

head -c 2GB /dev/urandom > /mnt/test/test.txt
head -c 4GB /dev/urandom > /mnt/backup/test.txt

[akavalov]

Thank you, rbuj.

[akavalov]

Indeed yours working as expected. This is strange. If someone else reports similar observation - then it will be different story. For now it seems I am the only one having this issue.
Not sure about "Test: create different/equal files at mount points /mnt/test and /mnt/backup and check the displayed values:". Is this for me to perform the tests, or you describing yours?
Thanks again.

[rbuj]

It's the brief description of the test I performed to reproduce your issue.

[akavalov]

Thank you. Appreciated your help. If you ever come across similar complain - please let me know.

[akavalov]

I was able to reproduce the bug. I rebuild the btrfs-raid1 over luks. All looked normal until i copied into this directory the SomeBigImage.iso file. System monitor Usage% jumped to 100% although I have free space on the disk.
Hope it helps.