100% Disk Space Used

Server has randomly started showing as 100% full "Total: 30720 MB Used: 30720 MB"

Files + database are no where near that amount. No idea whats using all the space.

forge@hulk:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/root        30G  4.4G   24G  16% /
devtmpfs        997M     0  997M   0% /dev
tmpfs           999M  4.0K  999M   1% /dev/shm
tmpfs           999M  9.7M  990M   1% /run
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           999M     0  999M   0% /sys/fs/cgroup
tmpfs           200M     0  200M   0% /run/user/1000
forge@hulk:~$ 

lsof | grep "(deleted)"
forge@hulk:~$ lsof | grep "(deleted)"
php-fpm7\. 11239                 forge    4u      REG                8,0        0       2170 /tmp/.ZendSem.sqYk9z (deleted)
php-fpm7\. 11249                 forge    4u      REG                8,0        0       2170 /tmp/.ZendSem.sqYk9z (deleted)
php-fpm7\. 11288                 forge    4u      REG                8,0        0       2170 /tmp/.ZendSem.sqYk9z (deleted)