If you use 4KB hard drives in FreeNAS you have to format them manually (ad8 is hard disk):
This will wipe your disk:
dd if=/dev/zero of=/dev/ad8 bs=1M count=10
Create partition:
gpt create ad8
gpt add –b 64 –s 3906994176 –t ufs /dev/ad8
newfs -S 4096 -b 32768 -f 4096 -O 2 -U -m 1 -o space -L F-disk /dev/ad8
Now reboot, and mount them but use CD/DVD or Old software RAID option when mounting!
If you want to tweak SAMBA add this to extra parameters:
socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192