yes I can install another hard drive on system.
please find df -h output as below:
Filesystem size Used Avial Use% Mounted on
/dev/sdc1 3.5G 740M 2.6G 23% /
tmpfs 2.0G 0 2.6G 0% /lib/init/rw
udev 2.0G 168K 2.0G 1% /dev
tmpfs 2.0G 0 2.0G 0% /dev/shm
tmpfs 2.0G 0 2.0G 0% /tmp
/dev/md127 917G 29G 889G 4% /media/8c1506de-b680-4404-9002-398cc5163df5
Also please see apt-get clean command output: Nothing happened I think because of I did that before from omv-extras plugin.