Issue

Following directories would be full because docker keeps open deleted files in /var/log/journal/

• /var/log directory
• /run directory

docker keeps open deleted files, so the disk space is not reclaimed and the volume fills itself.

# lsof /var/log/ | grep deleted | head -n 4
dockerd-c  1962     root  188r   REG  253,5  134217728 393243 /var/log/journal/b21c18bdf4504b179e7e5f603af451d7/system@cd9c4500ea1542078830cfa53d32045c-000000000143f319-00032a1115cf3795.journal (deleted)
dockerd-c  1962     root  281r   REG  253,5  134217728 393262 /var/log/journal/b21c18bdf4504b179e7e5f603af451d7/system@cd9c4500ea1542078830cfa53d32045c-00000000016bac54-00079a7673a25632.journal (deleted)
dockerd-c  1962     root  488r   REG  253,5  134217728 393257 /var/log/journal/b21c18bdf4504b179e7e5f603af451d7/system@cd9c4500ea1542078830cfa53d32045c-0000000001616409-00080a5af1b3991a.journal (deleted)
dockerd-c  1962     root  499r   REG  253,5  134217728 393240 /var/log/journal/b21c18bdf4504b179e7e5f603af451d7/system@cd9c4500ea1542078830cfa53d32045c-00000000013d8382-0007659ff3198e1la.journal (deleted)

# df -h /var/log/
Filesystem                      Size  Used Avail Use% Mounted on
/dev/mapper/root-lv   71G   68G  1.1G  99% /var/log
# du -sh /var/log/
41G     /var/log/

or 

# df -h
Filesystem             Size  Used Avail Use% Mounted on
.....
tmpfs                  3.9G  3.9G  0  100% /run