Jesse Reyes :
CircuitDaemon :
If it's just data without any OS or bootable software, why don't you just copy the files directly into the raid partition? Are they on a different server? could you elaborate on your current setup just to imagine the easiest approach?
Right, only data, no OS and no bootable sorftware. I thought about transferring the files over but some files may be protected and it may cause my data transfer to stop right in the middle and I may loose track of where I left off and with so many files it may be hard to figure out what copied and what not. That's why I thought of cloning, it will just copy everything with or without protection on the files.
Cloning with free software would be a little bit annoying since both partitions might not be the same size. You can use CloneZilla but I'd say it's too much trouble for something that simple.
For situations like yours, I like to use GoodSync but it's not free. They have a free to try version but you might run into limitations by the number of files. http://www.goodsync.com/
There's also teracopy, which will keep track of whatever cannot be copied and you can take note when the other files have finished being copied.
http://www.codesector.com/teracopy
I've used both and they work fine, but you may want to look at this list:
http://lifehacker.com/5280976/five-best-alternative-file-copiers
If you want to go the cloning route, Acronis True Image is able to use drives in RAID and will make any adjustments necessary to make the partition fit, but it's not free.