Can't login in WebGUI, SSH working, root is full

Dear community,

I am using OMV 3 with SnapRAID and Union filesystem (mergerfs). Everything was working fine.

I used the command

mv folder 1 folder 2 in the folder /srv/0b5379ae-d1cb-46a6-abf1-f79b680e4d2d

After a couple of minutes I got the error that the destination is full. I liked to check what's going on in the WebGUI but I couldn't login anymore.
In an other post I read that i have to check the root disk with df -h and yes my root disk is full:

Filesystem    Size  Used Avail Use% Mounted on
udev           10M     0   10M   0% /dev
tmpfs         3.2G  8.8M  3.2G   1% /run
/dev/sda1     106G  106G     0 100% /
tmpfs         7.9G     0  7.9G   0% /dev/shm
tmpfs         5.0M     0  5.0M   0% /run/lock
tmpfs         7.9G     0  7.9G   0% /sys/fs/cgroup
tmpfs         7.9G     0  7.9G   0% /tmp
/dev/sdd1     3.7T  794G  2.8T  22% /srv/dev-disk-by-id-ata-WDC_WD40EFRX-68N32N0_WD-WCC7K4DV8YTA-part1
/dev/sde1     3.7T  3.6T   35G 100% /srv/dev-disk-by-id-ata-WDC_WD40EFRX-68WT0N0_WD-WCC4E5ESCZUN-part1
/dev/sdb1     3.7T  3.6T   86G  98% /srv/dev-disk-by-id-ata-WDC_WD40EFRX-68WT0N0_WD-WCC4E5XX5S5J-part1
/dev/sdc1     3.7T  364M  3.6T   1% /srv/dev-disk-by-id-ata-WDC_WD40EFRX-68N32N0_WD-WCC7K0HRSCKE-part1

With google I can help myself with Linux but I am far from a professional linux user, therefore I don't know how I have to proceed.
How can I find the data I have to delete on sda1?
And for the future: How shall I move data on the merferfs "volume" without getting into the same problem?

Thanks for your help.

Regards,

I solved it myself. The command I used was

mv Videos /Media

which copied everything to the root Media folder and not to /srv/0b5379ae-d1cb-46a6-abf1-f79b680e4d2d/Media as I intended.

P.S.: I was in the /srv/ob53... folder

Hmmm strang thing is that I also have data in:

/srv/0b5379ae-d1cb-46a6-abf1-f79b680e4d2d/Media/Videos

so the move command did move something to the correct folder but also to /Media/Vidoes

I guess I will use the complete path information in the future.

I started now this command:

mv /srv/0b5379ae-d1cb-46a6-abf1-f79b680e4d2d/Videos/* /srv/0b5379ae-d1cb-46a6-abf1-f79b680e4d2d/Media/Videos/

What I don't understand is that the command is still running. It seems the system is copying the data and then deleting it. In windows I am used to it that as long as the data remains on the
same disk, only the pointer is changed. Does that mean that mergerfs can't handle "move" commands the same way and it is actually copying/deleting the data between disks?

you mean these, or?

/srv/dev-disk-by-id-ata-WDC_WD40EFRX-68N32N0_WD-WCC7K4DV8YTA-part1
/srv/dev-disk-by-id-ata-WDC_WD40EFRX-68WT0N0_WD-WCC4E5ESCZUN-part1
/srv/dev-disk-by-id-ata-WDC_WD40EFRX-68WT0N0_WD-WCC4E5XX5S5J-part1
/srv/dev-disk-by-id-ata-WDC_WD40EFRX-68N32N0_WD-WCC7K0HRSCKE-part1

Ok thank you.

Fun information:

Move now completed and snapraid diff results looks like this:

625 equal
0 added
197 removed
0 updated
74 moved
197 copied
0 restored

The "74 moved" were from the first command which "broke" the system (=> full OS disk). Second move command is recognized as copied and removed.