What is the Diffrence between Native NFS v.s NFS on OneFS ?

Hi All,

I've started to investigate an issue that is very strange , and until now no one had an solution for this.

Maybe some of the NFS Gurus can help here.

Client : CentOS 6.6 , 64Bit (Everything works NFSv3)

NFS Native Server Export : Export comes from a Linux Server with 2 x local drives SAS15K on it .

NFS OneFS Server Export : Export comes from a OneFS isilon ,S-200 with data on SSD.

Mount Exports are same on both exports from the client side.

Disabled Sync writes on Isilon.

The Scenario:

• Copy From Client to Native NFS Server - 0m35s
• Copy From Client to Isilon NFS Server - 1m55s

Is there any explanation of Why NFS Protocol will act this way on Isilon?

Remarks:  TcpDumps show that when doing the same action via Isilon it requires Double amounts of Request/Ansers 
                   Between Client <-> Isilon

No diffrence via MTU/Not diffrence of Network .... Same scenario diffrent target