Have large HDD, Formatted as ext4, labeled as gpt, only 2TB in size still

Today to my dismay I ran out of space on a disk in my server, confused as to why I checked with a few commands and I came up with a result that I don't understand.

Checking free space on drives,

df -h brings up the following.

Earlier I had set up /dev/sda to be an 8TB partition using parted

Starting with a bare drive I did the following parted /dev/sda mklabel gpt unit TB mkpart primary 0.00TB 8.00TB I print this output now and I'll get the following from /dev/sda

Telling me I have an 8TB partition.

I perform the lsblk command and come up with the result below.

I mounted the drive with mount

I am already in the process of copying back data from /dev/sda to /dev/sdc However, I am stumped as to why my drive only has a 2TB space for storage.

Perhaps I actually made the partition larger than the real drive space as reported by lsblk and this is why it doesn't work?