In the following output of df -h you can see that i have added a new hard drive(/dev/hdd1) and have mounted as /hdd1.

My question is if I start dumping data to /opt will that data be mounted in /hdd1 or /

My goal is to utilise the new hdd1 instead of old disk(/dev/sda3).

How can this be done?

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda3             442G  312G   12G  86% /
tmpfs                 1.9G     0  1.9G   0% /dev/shm
/dev/sda1             194M   57M  128M  31% /boot
/dev/sdb1             1.7T  201M  2.6T   1% /hdd1