Try this article:  [URL]  You can use similar steps to just copy the datastore from a local source to a NFS source.  However, you will need to point your datastore to the new location once it is done.
how to migrate Insight IQ datastore from a local datastore to a NFS DataStore on Isilon  i mean the exact procedure,  i know that i should stop the Insight IQ services first and then migrate it, but where can i find it and how should i export/import it?
how to migrate Insight IQ datastore from a local datastore to a NFS DataStore 
on Isilon