Dell Precision T5400 Workstation & HardDisk

My name's Muhammad and I'm from Egypt. I've bought a Dell Precision T5400 Workstation last year.

I'm really depressed, sad & confused ( I've searched many websites for my solution but all what I found were conflicting answers), so I decided to get here for the professionals and manufacturers - I'm sure they will reply quickly with the right answer.

I've 1 TB Western Digital (300 GB for Windows + 600 GB for personal files)

Now, I've decided to buy a 6TB WD HardDisk ONLY for storing big files in PC [such as games, videos, graphic, etc]
in addition to the existing 1TB WD HardDisk which will has Windows to boot from.

My question:
Will my 6TB WD HardDisk work well on my computer with no problems, and use all the space?!
Or motherboard, bios or controller have limit or something concerning HDD size?!

I'm really confused & sad and want a right answer 'cause the 6TB HardDisk here in Egypt costs 225$
(and it's a lot of money for me to save so I wanna make sure it will work well)

Thanks in advance!