ivanbgd,
I believe what albert was trying to get across to you is that for the most part Linux machines like the DNS 320 do not require or benefit from defragmentation as do Windows drives. Just because you can see it/ map it from your W7 machine does not make it a windows file system. If you google this you will find several explainations for why this is so. Here is one:
http://www.howtogeek.com/115229/htg-explains-why-linux-doesnt-need-defragmenting/