Time machine and RAID 5

If my hard drive is 3TB and my RAID 5 network system (wdc PR4100) is 4 x 2TB will I have problems backing up the drive with time machine once the drive goes beyond 2TB (computer hard drive)? I ask this because it is my understanding that one of the 4 drives is used for parity and the other 3 drives are written across evenly.