How to make sure the disk is filled-up by Docker and delete data?

I’m using the Graylog Docker installation which is included 3 images, the disk often fills up and I have to increase the volume and add storage to the server.

The thing is that Docker and Graylog show much use less than usage and how can sure that the dist is filled up by Docker?

$ df -h

Filesystem      Size  Used Avail Use% Mounted on
udev            1.9G     0  1.9G   0% /dev
tmpfs           390M  5.9M  384M   2% /run
/dev/nvme0n1p1   59G   49G  9.7G  84% /
tmpfs           2.0G     0  2.0G   0% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           2.0G     0  2.0G   0% /sys/fs/cgroup
/dev/loop0      100M  100M     0 100% /snap/core/10908
/dev/loop1       56M   56M     0 100% /snap/core18/1988
/dev/loop2       56M   56M     0 100% /snap/core18/1997
/dev/loop3       34M   34M     0 100% /snap/amazon-ssm-agent/3552
/dev/loop4       33M   33M     0 100% /snap/amazon-ssm-agent/2996
/dev/loop5      100M  100M     0 100% /snap/core/10958
tmpfs           390M     0  390M   0% /run/user/1000

sudo docker system df

TYPE                TOTAL               ACTIVE              SIZE                RECLAIMABLE
Images              3                   3                   1.663GB             0B (0%)
Containers          3                   3                   5.735GB             0B (0%)
Local Volumes       6                   3                   579.6MB             44.89MB (7%)
Build Cache         0                   0                   0B                  0B

sudo docker stats --all

CONTAINER ID        NAME                 CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
8e8b6d5d8a18        suspicious_hodgkin   2.33%               464.8MiB / 3.801GiB   11.94%              193MB / 179MB       167MB / 30MB        190
086eb23cbe62        elasticsearch        42.20%              832.1MiB / 3.801GiB   21.38%              19.1MB / 14.1MB     303MB / 552MB       47
9f5be3b38814        mongo                1.61%               43.12MiB / 3.801GiB   1.11%               151MB / 168MB       50.6MB / 126MB      31

And Graylog Indices

enter image description here