Hi,

we need to migrate file cluster on 2003 server to windows server 2008.

how i can do that?

Hi,

here's the Clustered File Services Migration Guide

Hi Aperelli,

Thanks for your replay, we are not using DFS just clustering 

This includes DFS but as the first line reads:

"This document provides guidance for migrating the File Services server role, including data, shared folders, and operating system settings from the source server to the destination server that is running Windows Server 2008 R2."

i think this is much easier and simple

https://technet.microsoft.com/en-us/library/cc754481(WS.10).aspx

do i have to use any other migration tool such as file server migration tool

It's your migration, follow the guide that suites you best. The one you are pointing to is not specific for file service tough. 

About the file migration tool here's a good article

so it is better to use robocopy or file server migration

It depends on multiple factors, I think is well explained in the article I sent you